diff --git a/lib/js/src/tea.js b/lib/js/src/tea.js
index 24d97bc..172eac9 100644
--- a/lib/js/src/tea.js
+++ b/lib/js/src/tea.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 
diff --git a/lib/js/src/tea_animationframe.js b/lib/js/src/tea_animationframe.js
index 8f46a43..d0a3e70 100644
--- a/lib/js/src/tea_animationframe.js
+++ b/lib/js/src/tea_animationframe.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 var Curry = require("bs-platform/lib/js/curry.js");
diff --git a/lib/js/src/tea_app.js b/lib/js/src/tea_app.js
index c55931d..284b41c 100644
--- a/lib/js/src/tea_app.js
+++ b/lib/js/src/tea_app.js
@@ -1,12 +1,12 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 var Web = require("./web.js");
-var List = require("bs-platform/lib/js/list.js");
 var Vdom = require("./vdom.js");
 var Curry = require("bs-platform/lib/js/curry.js");
 var Tea_cmd = require("./tea_cmd.js");
 var Tea_sub = require("./tea_sub.js");
+var Belt_List = require("bs-platform/lib/js/belt_List.js");
 var Caml_builtin_exceptions = require("bs-platform/lib/js/caml_builtin_exceptions.js");
 
 function programStateWrapper(initModel, pump, shutdown) {
@@ -34,7 +34,7 @@ function programStateWrapper(initModel, pump, shutdown) {
         var msgs = match$1[0];
         if (msgs) {
           pending[0] = /* None */0;
-          return List.iter(handler, List.rev(msgs));
+          return Belt_List.forEach(Belt_List.reverse(msgs), handler);
         } else {
           pending[0] = /* None */0;
           return /* () */0;
diff --git a/lib/js/src/tea_cmd.js b/lib/js/src/tea_cmd.js
index ec98c0a..0418df9 100644
--- a/lib/js/src/tea_cmd.js
+++ b/lib/js/src/tea_cmd.js
@@ -1,10 +1,10 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
-var List = require("bs-platform/lib/js/list.js");
 var Vdom = require("./vdom.js");
 var Block = require("bs-platform/lib/js/block.js");
 var Curry = require("bs-platform/lib/js/curry.js");
+var Belt_List = require("bs-platform/lib/js/belt_List.js");
 
 function batch(cmds) {
   return /* Batch */Block.__(1, [cmds]);
@@ -32,9 +32,9 @@ function run(callbacks, param) {
   } else {
     switch (param.tag | 0) {
       case 1 : 
-          return List.fold_left((function (_, cmd) {
+          return Belt_List.reduceU(param[0], /* () */0, (function (_, cmd) {
                         return run(callbacks, cmd);
-                      }), /* () */0, param[0]);
+                      }));
       case 0 : 
       case 2 : 
           return Curry._1(param[0], callbacks);
diff --git a/lib/js/src/tea_ex.js b/lib/js/src/tea_ex.js
index 9fc6cb5..0b24aef 100644
--- a/lib/js/src/tea_ex.js
+++ b/lib/js/src/tea_ex.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 var Block = require("bs-platform/lib/js/block.js");
diff --git a/lib/js/src/tea_html.js b/lib/js/src/tea_html.js
index fc43eae..9c5f45c 100644
--- a/lib/js/src/tea_html.js
+++ b/lib/js/src/tea_html.js
@@ -1,11 +1,11 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
-var List = require("bs-platform/lib/js/list.js");
 var Vdom = require("./vdom.js");
 var Block = require("bs-platform/lib/js/block.js");
 var Curry = require("bs-platform/lib/js/curry.js");
 var $$String = require("bs-platform/lib/js/string.js");
+var Belt_List = require("bs-platform/lib/js/belt_List.js");
 
 function text(str) {
   return /* Text */Block.__(1, [str]);
@@ -613,11 +613,11 @@ function class$prime(name) {
 }
 
 function classList(classes) {
-  var name = $$String.concat(" ", List.map((function (param) {
+  var name = $$String.concat(" ", Belt_List.map(Belt_List.keep(classes, (function (param) {
+                  return param[1];
+                })), (function (param) {
               return param[0];
-            }), List.filter((function (param) {
-                    return param[1];
-                  }))(classes)));
+            })));
   return /* RawProp */Block.__(0, [
             "className",
             name
diff --git a/lib/js/src/tea_html_cmds.js b/lib/js/src/tea_html_cmds.js
index da237a6..61d045e 100644
--- a/lib/js/src/tea_html_cmds.js
+++ b/lib/js/src/tea_html_cmds.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 var Block = require("bs-platform/lib/js/block.js");
diff --git a/lib/js/src/tea_http.js b/lib/js/src/tea_http.js
index b44813b..1984a50 100644
--- a/lib/js/src/tea_http.js
+++ b/lib/js/src/tea_http.js
@@ -1,13 +1,12 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
-var List = require("bs-platform/lib/js/list.js");
 var Block = require("bs-platform/lib/js/block.js");
 var Curry = require("bs-platform/lib/js/curry.js");
 var Tea_json = require("./tea_json.js");
-var Caml_primitive = require("bs-platform/lib/js/caml_primitive.js");
+var Belt_List = require("bs-platform/lib/js/belt_List.js");
+var Belt_MapString = require("bs-platform/lib/js/belt_MapString.js");
 var Web_xmlhttprequest = require("./web_xmlhttprequest.js");
-var Caml_builtin_exceptions = require("bs-platform/lib/js/caml_builtin_exceptions.js");
 
 function string_of_error(param) {
   if (typeof param === "number") {
@@ -83,482 +82,6 @@ function getString(url) {
 function send(resultToMessage, param) {
   var maybeEvents = param[1];
   var request = param[0];
-  var height = function (param) {
-    if (param) {
-      return param[4];
-    } else {
-      return 0;
-    }
-  };
-  var create = function (l, x, d, r) {
-    var hl = height(l);
-    var hr = height(r);
-    return /* Node */[
-            l,
-            x,
-            d,
-            r,
-            hl >= hr ? hl + 1 | 0 : hr + 1 | 0
-          ];
-  };
-  var singleton = function (x, d) {
-    return /* Node */[
-            /* Empty */0,
-            x,
-            d,
-            /* Empty */0,
-            1
-          ];
-  };
-  var bal = function (l, x, d, r) {
-    var hl = l ? l[4] : 0;
-    var hr = r ? r[4] : 0;
-    if (hl > (hr + 2 | 0)) {
-      if (l) {
-        var lr = l[3];
-        var ld = l[2];
-        var lv = l[1];
-        var ll = l[0];
-        if (height(ll) >= height(lr)) {
-          return create(ll, lv, ld, create(lr, x, d, r));
-        } else if (lr) {
-          return create(create(ll, lv, ld, lr[0]), lr[1], lr[2], create(lr[3], x, d, r));
-        } else {
-          throw [
-                Caml_builtin_exceptions.invalid_argument,
-                "Map.bal"
-              ];
-        }
-      } else {
-        throw [
-              Caml_builtin_exceptions.invalid_argument,
-              "Map.bal"
-            ];
-      }
-    } else if (hr > (hl + 2 | 0)) {
-      if (r) {
-        var rr = r[3];
-        var rd = r[2];
-        var rv = r[1];
-        var rl = r[0];
-        if (height(rr) >= height(rl)) {
-          return create(create(l, x, d, rl), rv, rd, rr);
-        } else if (rl) {
-          return create(create(l, x, d, rl[0]), rl[1], rl[2], create(rl[3], rv, rd, rr));
-        } else {
-          throw [
-                Caml_builtin_exceptions.invalid_argument,
-                "Map.bal"
-              ];
-        }
-      } else {
-        throw [
-              Caml_builtin_exceptions.invalid_argument,
-              "Map.bal"
-            ];
-      }
-    } else {
-      return /* Node */[
-              l,
-              x,
-              d,
-              r,
-              hl >= hr ? hl + 1 | 0 : hr + 1 | 0
-            ];
-    }
-  };
-  var add = function (x, data, param) {
-    if (param) {
-      var r = param[3];
-      var d = param[2];
-      var v = param[1];
-      var l = param[0];
-      var c = Caml_primitive.caml_string_compare(x, v);
-      if (c) {
-        if (c < 0) {
-          return bal(add(x, data, l), v, d, r);
-        } else {
-          return bal(l, v, d, add(x, data, r));
-        }
-      } else {
-        return /* Node */[
-                l,
-                x,
-                data,
-                r,
-                param[4]
-              ];
-      }
-    } else {
-      return /* Node */[
-              /* Empty */0,
-              x,
-              data,
-              /* Empty */0,
-              1
-            ];
-    }
-  };
-  var min_binding = function (_param) {
-    while(true) {
-      var param = _param;
-      if (param) {
-        var l = param[0];
-        if (l) {
-          _param = l;
-          continue ;
-          
-        } else {
-          return /* tuple */[
-                  param[1],
-                  param[2]
-                ];
-        }
-      } else {
-        throw Caml_builtin_exceptions.not_found;
-      }
-    };
-  };
-  var remove_min_binding = function (param) {
-    if (param) {
-      var l = param[0];
-      if (l) {
-        return bal(remove_min_binding(l), param[1], param[2], param[3]);
-      } else {
-        return param[3];
-      }
-    } else {
-      throw [
-            Caml_builtin_exceptions.invalid_argument,
-            "Map.remove_min_elt"
-          ];
-    }
-  };
-  var remove = function (x, param) {
-    if (param) {
-      var r = param[3];
-      var d = param[2];
-      var v = param[1];
-      var l = param[0];
-      var c = Caml_primitive.caml_string_compare(x, v);
-      if (c) {
-        if (c < 0) {
-          return bal(remove(x, l), v, d, r);
-        } else {
-          return bal(l, v, d, remove(x, r));
-        }
-      } else {
-        var t1 = l;
-        var t2 = r;
-        if (t1) {
-          if (t2) {
-            var match = min_binding(t2);
-            return bal(t1, match[0], match[1], remove_min_binding(t2));
-          } else {
-            return t1;
-          }
-        } else {
-          return t2;
-        }
-      }
-    } else {
-      return /* Empty */0;
-    }
-  };
-  var iter = function (f, _param) {
-    while(true) {
-      var param = _param;
-      if (param) {
-        iter(f, param[0]);
-        Curry._2(f, param[1], param[2]);
-        _param = param[3];
-        continue ;
-        
-      } else {
-        return /* () */0;
-      }
-    };
-  };
-  var map = function (f, param) {
-    if (param) {
-      var l$prime = map(f, param[0]);
-      var d$prime = Curry._1(f, param[2]);
-      var r$prime = map(f, param[3]);
-      return /* Node */[
-              l$prime,
-              param[1],
-              d$prime,
-              r$prime,
-              param[4]
-            ];
-    } else {
-      return /* Empty */0;
-    }
-  };
-  var mapi = function (f, param) {
-    if (param) {
-      var v = param[1];
-      var l$prime = mapi(f, param[0]);
-      var d$prime = Curry._2(f, v, param[2]);
-      var r$prime = mapi(f, param[3]);
-      return /* Node */[
-              l$prime,
-              v,
-              d$prime,
-              r$prime,
-              param[4]
-            ];
-    } else {
-      return /* Empty */0;
-    }
-  };
-  var fold = function (f, _m, _accu) {
-    while(true) {
-      var accu = _accu;
-      var m = _m;
-      if (m) {
-        _accu = Curry._3(f, m[1], m[2], fold(f, m[0], accu));
-        _m = m[3];
-        continue ;
-        
-      } else {
-        return accu;
-      }
-    };
-  };
-  var for_all = function (p, _param) {
-    while(true) {
-      var param = _param;
-      if (param) {
-        if (Curry._2(p, param[1], param[2])) {
-          if (for_all(p, param[0])) {
-            _param = param[3];
-            continue ;
-            
-          } else {
-            return /* false */0;
-          }
-        } else {
-          return /* false */0;
-        }
-      } else {
-        return /* true */1;
-      }
-    };
-  };
-  var exists = function (p, _param) {
-    while(true) {
-      var param = _param;
-      if (param) {
-        if (Curry._2(p, param[1], param[2])) {
-          return /* true */1;
-        } else if (exists(p, param[0])) {
-          return /* true */1;
-        } else {
-          _param = param[3];
-          continue ;
-          
-        }
-      } else {
-        return /* false */0;
-      }
-    };
-  };
-  var add_min_binding = function (k, v, param) {
-    if (param) {
-      return bal(add_min_binding(k, v, param[0]), param[1], param[2], param[3]);
-    } else {
-      return singleton(k, v);
-    }
-  };
-  var add_max_binding = function (k, v, param) {
-    if (param) {
-      return bal(param[0], param[1], param[2], add_max_binding(k, v, param[3]));
-    } else {
-      return singleton(k, v);
-    }
-  };
-  var join = function (l, v, d, r) {
-    if (l) {
-      if (r) {
-        var rh = r[4];
-        var lh = l[4];
-        if (lh > (rh + 2 | 0)) {
-          return bal(l[0], l[1], l[2], join(l[3], v, d, r));
-        } else if (rh > (lh + 2 | 0)) {
-          return bal(join(l, v, d, r[0]), r[1], r[2], r[3]);
-        } else {
-          return create(l, v, d, r);
-        }
-      } else {
-        return add_max_binding(v, d, l);
-      }
-    } else {
-      return add_min_binding(v, d, r);
-    }
-  };
-  var concat = function (t1, t2) {
-    if (t1) {
-      if (t2) {
-        var match = min_binding(t2);
-        return join(t1, match[0], match[1], remove_min_binding(t2));
-      } else {
-        return t1;
-      }
-    } else {
-      return t2;
-    }
-  };
-  var concat_or_join = function (t1, v, d, t2) {
-    if (d) {
-      return join(t1, v, d[0], t2);
-    } else {
-      return concat(t1, t2);
-    }
-  };
-  var split = function (x, param) {
-    if (param) {
-      var r = param[3];
-      var d = param[2];
-      var v = param[1];
-      var l = param[0];
-      var c = Caml_primitive.caml_string_compare(x, v);
-      if (c) {
-        if (c < 0) {
-          var match = split(x, l);
-          return /* tuple */[
-                  match[0],
-                  match[1],
-                  join(match[2], v, d, r)
-                ];
-        } else {
-          var match$1 = split(x, r);
-          return /* tuple */[
-                  join(l, v, d, match$1[0]),
-                  match$1[1],
-                  match$1[2]
-                ];
-        }
-      } else {
-        return /* tuple */[
-                l,
-                /* Some */[d],
-                r
-              ];
-      }
-    } else {
-      return /* tuple */[
-              /* Empty */0,
-              /* None */0,
-              /* Empty */0
-            ];
-    }
-  };
-  var merge = function (f, s1, s2) {
-    var exit = 0;
-    if (s1) {
-      var v1 = s1[1];
-      if (s1[4] >= height(s2)) {
-        var match = split(v1, s2);
-        return concat_or_join(merge(f, s1[0], match[0]), v1, Curry._3(f, v1, /* Some */[s1[2]], match[1]), merge(f, s1[3], match[2]));
-      } else {
-        exit = 1;
-      }
-    } else if (s2) {
-      exit = 1;
-    } else {
-      return /* Empty */0;
-    }
-    if (exit === 1) {
-      if (s2) {
-        var v2 = s2[1];
-        var match$1 = split(v2, s1);
-        return concat_or_join(merge(f, match$1[0], s2[0]), v2, Curry._3(f, v2, match$1[1], /* Some */[s2[2]]), merge(f, match$1[2], s2[3]));
-      } else {
-        throw [
-              Caml_builtin_exceptions.assert_failure,
-              [
-                "map.ml",
-                270,
-                10
-              ]
-            ];
-      }
-    }
-    
-  };
-  var filter = function (p, param) {
-    if (param) {
-      var d = param[2];
-      var v = param[1];
-      var l$prime = filter(p, param[0]);
-      var pvd = Curry._2(p, v, d);
-      var r$prime = filter(p, param[3]);
-      if (pvd) {
-        return join(l$prime, v, d, r$prime);
-      } else {
-        return concat(l$prime, r$prime);
-      }
-    } else {
-      return /* Empty */0;
-    }
-  };
-  var partition = function (p, param) {
-    if (param) {
-      var d = param[2];
-      var v = param[1];
-      var match = partition(p, param[0]);
-      var lf = match[1];
-      var lt = match[0];
-      var pvd = Curry._2(p, v, d);
-      var match$1 = partition(p, param[3]);
-      var rf = match$1[1];
-      var rt = match$1[0];
-      if (pvd) {
-        return /* tuple */[
-                join(lt, v, d, rt),
-                concat(lf, rf)
-              ];
-      } else {
-        return /* tuple */[
-                concat(lt, rt),
-                join(lf, v, d, rf)
-              ];
-      }
-    } else {
-      return /* tuple */[
-              /* Empty */0,
-              /* Empty */0
-            ];
-    }
-  };
-  var cardinal = function (param) {
-    if (param) {
-      return (cardinal(param[0]) + 1 | 0) + cardinal(param[3]) | 0;
-    } else {
-      return 0;
-    }
-  };
-  var bindings_aux = function (_accu, _param) {
-    while(true) {
-      var param = _param;
-      var accu = _accu;
-      if (param) {
-        _param = param[0];
-        _accu = /* :: */[
-          /* tuple */[
-            param[1],
-            param[2]
-          ],
-          bindings_aux(accu, param[3])
-        ];
-        continue ;
-        
-      } else {
-        return accu;
-      }
-    };
-  };
   var expect = request[/* expect */4];
   var responseToResult = expect[1];
   var typ = expect[0];
@@ -583,10 +106,12 @@ function send(resultToMessage, param) {
                     }
                   };
                   mayCB((function (param) {
-                          return xhr.onreadystatechange = param;
+                          xhr.onreadystatechange = param;
+                          return /* () */0;
                         }), match[/* onreadystatechange */0]);
                   mayCB((function (param) {
-                          return xhr.onprogress = param;
+                          xhr.onprogress = param;
+                          return /* () */0;
                         }), match[/* onprogress */1]);
                 }
                 var partial_arg = /* Error */Block.__(1, [/* NetworkError */1]);
@@ -607,7 +132,7 @@ function send(resultToMessage, param) {
                 var cb$3 = function () {
                   var match = Web_xmlhttprequest.getAllResponseHeadersAsDict(xhr);
                   var headers;
-                  headers = match.tag ? /* Empty */0 : match[0];
+                  headers = match.tag ? Belt_MapString.empty : match[0];
                   var response_000 = /* url */xhr.responseURL;
                   var response_001 = /* status : record */[
                     /* code */xhr.status,
@@ -656,7 +181,7 @@ function send(resultToMessage, param) {
                 var setHeader = function (param) {
                   return Web_xmlhttprequest.setRequestHeader(param[0], param[1], xhr);
                 };
-                List.iter(setHeader, headers);
+                Belt_List.forEach(headers, setHeader);
                 Web_xmlhttprequest.set_responseType(typ, xhr);
                 if (timeout) {
                   xhr.timeout = timeout[0];
diff --git a/lib/js/src/tea_json.js b/lib/js/src/tea_json.js
index 9b52ff5..6f7339b 100644
--- a/lib/js/src/tea_json.js
+++ b/lib/js/src/tea_json.js
@@ -1,698 +1,19 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
-var List = require("bs-platform/lib/js/list.js");
 var $$Array = require("bs-platform/lib/js/array.js");
 var Block = require("bs-platform/lib/js/block.js");
 var Curry = require("bs-platform/lib/js/curry.js");
 var Js_exn = require("bs-platform/lib/js/js_exn.js");
 var Web_json = require("./web_json.js");
-var Caml_array = require("bs-platform/lib/js/caml_array.js");
+var Belt_List = require("bs-platform/lib/js/belt_List.js");
+var Belt_Array = require("bs-platform/lib/js/belt_Array.js");
 var Pervasives = require("bs-platform/lib/js/pervasives.js");
 var Tea_result = require("./tea_result.js");
-var Caml_primitive = require("bs-platform/lib/js/caml_primitive.js");
+var Belt_MapString = require("bs-platform/lib/js/belt_MapString.js");
 var Caml_exceptions = require("bs-platform/lib/js/caml_exceptions.js");
 var Caml_builtin_exceptions = require("bs-platform/lib/js/caml_builtin_exceptions.js");
 
-function height(param) {
-  if (param) {
-    return param[4];
-  } else {
-    return 0;
-  }
-}
-
-function create(l, x, d, r) {
-  var hl = height(l);
-  var hr = height(r);
-  return /* Node */[
-          l,
-          x,
-          d,
-          r,
-          hl >= hr ? hl + 1 | 0 : hr + 1 | 0
-        ];
-}
-
-function singleton(x, d) {
-  return /* Node */[
-          /* Empty */0,
-          x,
-          d,
-          /* Empty */0,
-          1
-        ];
-}
-
-function bal(l, x, d, r) {
-  var hl = l ? l[4] : 0;
-  var hr = r ? r[4] : 0;
-  if (hl > (hr + 2 | 0)) {
-    if (l) {
-      var lr = l[3];
-      var ld = l[2];
-      var lv = l[1];
-      var ll = l[0];
-      if (height(ll) >= height(lr)) {
-        return create(ll, lv, ld, create(lr, x, d, r));
-      } else if (lr) {
-        return create(create(ll, lv, ld, lr[0]), lr[1], lr[2], create(lr[3], x, d, r));
-      } else {
-        throw [
-              Caml_builtin_exceptions.invalid_argument,
-              "Map.bal"
-            ];
-      }
-    } else {
-      throw [
-            Caml_builtin_exceptions.invalid_argument,
-            "Map.bal"
-          ];
-    }
-  } else if (hr > (hl + 2 | 0)) {
-    if (r) {
-      var rr = r[3];
-      var rd = r[2];
-      var rv = r[1];
-      var rl = r[0];
-      if (height(rr) >= height(rl)) {
-        return create(create(l, x, d, rl), rv, rd, rr);
-      } else if (rl) {
-        return create(create(l, x, d, rl[0]), rl[1], rl[2], create(rl[3], rv, rd, rr));
-      } else {
-        throw [
-              Caml_builtin_exceptions.invalid_argument,
-              "Map.bal"
-            ];
-      }
-    } else {
-      throw [
-            Caml_builtin_exceptions.invalid_argument,
-            "Map.bal"
-          ];
-    }
-  } else {
-    return /* Node */[
-            l,
-            x,
-            d,
-            r,
-            hl >= hr ? hl + 1 | 0 : hr + 1 | 0
-          ];
-  }
-}
-
-function is_empty(param) {
-  if (param) {
-    return /* false */0;
-  } else {
-    return /* true */1;
-  }
-}
-
-function add(x, data, param) {
-  if (param) {
-    var r = param[3];
-    var d = param[2];
-    var v = param[1];
-    var l = param[0];
-    var c = Caml_primitive.caml_string_compare(x, v);
-    if (c) {
-      if (c < 0) {
-        return bal(add(x, data, l), v, d, r);
-      } else {
-        return bal(l, v, d, add(x, data, r));
-      }
-    } else {
-      return /* Node */[
-              l,
-              x,
-              data,
-              r,
-              param[4]
-            ];
-    }
-  } else {
-    return /* Node */[
-            /* Empty */0,
-            x,
-            data,
-            /* Empty */0,
-            1
-          ];
-  }
-}
-
-function find(x, _param) {
-  while(true) {
-    var param = _param;
-    if (param) {
-      var c = Caml_primitive.caml_string_compare(x, param[1]);
-      if (c) {
-        _param = c < 0 ? param[0] : param[3];
-        continue ;
-        
-      } else {
-        return param[2];
-      }
-    } else {
-      throw Caml_builtin_exceptions.not_found;
-    }
-  };
-}
-
-function mem(x, _param) {
-  while(true) {
-    var param = _param;
-    if (param) {
-      var c = Caml_primitive.caml_string_compare(x, param[1]);
-      if (c) {
-        _param = c < 0 ? param[0] : param[3];
-        continue ;
-        
-      } else {
-        return /* true */1;
-      }
-    } else {
-      return /* false */0;
-    }
-  };
-}
-
-function min_binding(_param) {
-  while(true) {
-    var param = _param;
-    if (param) {
-      var l = param[0];
-      if (l) {
-        _param = l;
-        continue ;
-        
-      } else {
-        return /* tuple */[
-                param[1],
-                param[2]
-              ];
-      }
-    } else {
-      throw Caml_builtin_exceptions.not_found;
-    }
-  };
-}
-
-function max_binding(_param) {
-  while(true) {
-    var param = _param;
-    if (param) {
-      var r = param[3];
-      if (r) {
-        _param = r;
-        continue ;
-        
-      } else {
-        return /* tuple */[
-                param[1],
-                param[2]
-              ];
-      }
-    } else {
-      throw Caml_builtin_exceptions.not_found;
-    }
-  };
-}
-
-function remove_min_binding(param) {
-  if (param) {
-    var l = param[0];
-    if (l) {
-      return bal(remove_min_binding(l), param[1], param[2], param[3]);
-    } else {
-      return param[3];
-    }
-  } else {
-    throw [
-          Caml_builtin_exceptions.invalid_argument,
-          "Map.remove_min_elt"
-        ];
-  }
-}
-
-function remove(x, param) {
-  if (param) {
-    var r = param[3];
-    var d = param[2];
-    var v = param[1];
-    var l = param[0];
-    var c = Caml_primitive.caml_string_compare(x, v);
-    if (c) {
-      if (c < 0) {
-        return bal(remove(x, l), v, d, r);
-      } else {
-        return bal(l, v, d, remove(x, r));
-      }
-    } else {
-      var t1 = l;
-      var t2 = r;
-      if (t1) {
-        if (t2) {
-          var match = min_binding(t2);
-          return bal(t1, match[0], match[1], remove_min_binding(t2));
-        } else {
-          return t1;
-        }
-      } else {
-        return t2;
-      }
-    }
-  } else {
-    return /* Empty */0;
-  }
-}
-
-function iter(f, _param) {
-  while(true) {
-    var param = _param;
-    if (param) {
-      iter(f, param[0]);
-      Curry._2(f, param[1], param[2]);
-      _param = param[3];
-      continue ;
-      
-    } else {
-      return /* () */0;
-    }
-  };
-}
-
-function map(f, param) {
-  if (param) {
-    var l$prime = map(f, param[0]);
-    var d$prime = Curry._1(f, param[2]);
-    var r$prime = map(f, param[3]);
-    return /* Node */[
-            l$prime,
-            param[1],
-            d$prime,
-            r$prime,
-            param[4]
-          ];
-  } else {
-    return /* Empty */0;
-  }
-}
-
-function mapi(f, param) {
-  if (param) {
-    var v = param[1];
-    var l$prime = mapi(f, param[0]);
-    var d$prime = Curry._2(f, v, param[2]);
-    var r$prime = mapi(f, param[3]);
-    return /* Node */[
-            l$prime,
-            v,
-            d$prime,
-            r$prime,
-            param[4]
-          ];
-  } else {
-    return /* Empty */0;
-  }
-}
-
-function fold(f, _m, _accu) {
-  while(true) {
-    var accu = _accu;
-    var m = _m;
-    if (m) {
-      _accu = Curry._3(f, m[1], m[2], fold(f, m[0], accu));
-      _m = m[3];
-      continue ;
-      
-    } else {
-      return accu;
-    }
-  };
-}
-
-function for_all(p, _param) {
-  while(true) {
-    var param = _param;
-    if (param) {
-      if (Curry._2(p, param[1], param[2])) {
-        if (for_all(p, param[0])) {
-          _param = param[3];
-          continue ;
-          
-        } else {
-          return /* false */0;
-        }
-      } else {
-        return /* false */0;
-      }
-    } else {
-      return /* true */1;
-    }
-  };
-}
-
-function exists(p, _param) {
-  while(true) {
-    var param = _param;
-    if (param) {
-      if (Curry._2(p, param[1], param[2])) {
-        return /* true */1;
-      } else if (exists(p, param[0])) {
-        return /* true */1;
-      } else {
-        _param = param[3];
-        continue ;
-        
-      }
-    } else {
-      return /* false */0;
-    }
-  };
-}
-
-function add_min_binding(k, v, param) {
-  if (param) {
-    return bal(add_min_binding(k, v, param[0]), param[1], param[2], param[3]);
-  } else {
-    return singleton(k, v);
-  }
-}
-
-function add_max_binding(k, v, param) {
-  if (param) {
-    return bal(param[0], param[1], param[2], add_max_binding(k, v, param[3]));
-  } else {
-    return singleton(k, v);
-  }
-}
-
-function join(l, v, d, r) {
-  if (l) {
-    if (r) {
-      var rh = r[4];
-      var lh = l[4];
-      if (lh > (rh + 2 | 0)) {
-        return bal(l[0], l[1], l[2], join(l[3], v, d, r));
-      } else if (rh > (lh + 2 | 0)) {
-        return bal(join(l, v, d, r[0]), r[1], r[2], r[3]);
-      } else {
-        return create(l, v, d, r);
-      }
-    } else {
-      return add_max_binding(v, d, l);
-    }
-  } else {
-    return add_min_binding(v, d, r);
-  }
-}
-
-function concat(t1, t2) {
-  if (t1) {
-    if (t2) {
-      var match = min_binding(t2);
-      return join(t1, match[0], match[1], remove_min_binding(t2));
-    } else {
-      return t1;
-    }
-  } else {
-    return t2;
-  }
-}
-
-function concat_or_join(t1, v, d, t2) {
-  if (d) {
-    return join(t1, v, d[0], t2);
-  } else {
-    return concat(t1, t2);
-  }
-}
-
-function split(x, param) {
-  if (param) {
-    var r = param[3];
-    var d = param[2];
-    var v = param[1];
-    var l = param[0];
-    var c = Caml_primitive.caml_string_compare(x, v);
-    if (c) {
-      if (c < 0) {
-        var match = split(x, l);
-        return /* tuple */[
-                match[0],
-                match[1],
-                join(match[2], v, d, r)
-              ];
-      } else {
-        var match$1 = split(x, r);
-        return /* tuple */[
-                join(l, v, d, match$1[0]),
-                match$1[1],
-                match$1[2]
-              ];
-      }
-    } else {
-      return /* tuple */[
-              l,
-              /* Some */[d],
-              r
-            ];
-    }
-  } else {
-    return /* tuple */[
-            /* Empty */0,
-            /* None */0,
-            /* Empty */0
-          ];
-  }
-}
-
-function merge(f, s1, s2) {
-  var exit = 0;
-  if (s1) {
-    var v1 = s1[1];
-    if (s1[4] >= height(s2)) {
-      var match = split(v1, s2);
-      return concat_or_join(merge(f, s1[0], match[0]), v1, Curry._3(f, v1, /* Some */[s1[2]], match[1]), merge(f, s1[3], match[2]));
-    } else {
-      exit = 1;
-    }
-  } else if (s2) {
-    exit = 1;
-  } else {
-    return /* Empty */0;
-  }
-  if (exit === 1) {
-    if (s2) {
-      var v2 = s2[1];
-      var match$1 = split(v2, s1);
-      return concat_or_join(merge(f, match$1[0], s2[0]), v2, Curry._3(f, v2, match$1[1], /* Some */[s2[2]]), merge(f, match$1[2], s2[3]));
-    } else {
-      throw [
-            Caml_builtin_exceptions.assert_failure,
-            [
-              "map.ml",
-              270,
-              10
-            ]
-          ];
-    }
-  }
-  
-}
-
-function filter(p, param) {
-  if (param) {
-    var d = param[2];
-    var v = param[1];
-    var l$prime = filter(p, param[0]);
-    var pvd = Curry._2(p, v, d);
-    var r$prime = filter(p, param[3]);
-    if (pvd) {
-      return join(l$prime, v, d, r$prime);
-    } else {
-      return concat(l$prime, r$prime);
-    }
-  } else {
-    return /* Empty */0;
-  }
-}
-
-function partition(p, param) {
-  if (param) {
-    var d = param[2];
-    var v = param[1];
-    var match = partition(p, param[0]);
-    var lf = match[1];
-    var lt = match[0];
-    var pvd = Curry._2(p, v, d);
-    var match$1 = partition(p, param[3]);
-    var rf = match$1[1];
-    var rt = match$1[0];
-    if (pvd) {
-      return /* tuple */[
-              join(lt, v, d, rt),
-              concat(lf, rf)
-            ];
-    } else {
-      return /* tuple */[
-              concat(lt, rt),
-              join(lf, v, d, rf)
-            ];
-    }
-  } else {
-    return /* tuple */[
-            /* Empty */0,
-            /* Empty */0
-          ];
-  }
-}
-
-function cons_enum(_m, _e) {
-  while(true) {
-    var e = _e;
-    var m = _m;
-    if (m) {
-      _e = /* More */[
-        m[1],
-        m[2],
-        m[3],
-        e
-      ];
-      _m = m[0];
-      continue ;
-      
-    } else {
-      return e;
-    }
-  };
-}
-
-function compare(cmp, m1, m2) {
-  var _e1 = cons_enum(m1, /* End */0);
-  var _e2 = cons_enum(m2, /* End */0);
-  while(true) {
-    var e2 = _e2;
-    var e1 = _e1;
-    if (e1) {
-      if (e2) {
-        var c = Caml_primitive.caml_string_compare(e1[0], e2[0]);
-        if (c !== 0) {
-          return c;
-        } else {
-          var c$1 = Curry._2(cmp, e1[1], e2[1]);
-          if (c$1 !== 0) {
-            return c$1;
-          } else {
-            _e2 = cons_enum(e2[2], e2[3]);
-            _e1 = cons_enum(e1[2], e1[3]);
-            continue ;
-            
-          }
-        }
-      } else {
-        return 1;
-      }
-    } else if (e2) {
-      return -1;
-    } else {
-      return 0;
-    }
-  };
-}
-
-function equal(cmp, m1, m2) {
-  var _e1 = cons_enum(m1, /* End */0);
-  var _e2 = cons_enum(m2, /* End */0);
-  while(true) {
-    var e2 = _e2;
-    var e1 = _e1;
-    if (e1) {
-      if (e2) {
-        if (Caml_primitive.caml_string_compare(e1[0], e2[0])) {
-          return /* false */0;
-        } else if (Curry._2(cmp, e1[1], e2[1])) {
-          _e2 = cons_enum(e2[2], e2[3]);
-          _e1 = cons_enum(e1[2], e1[3]);
-          continue ;
-          
-        } else {
-          return /* false */0;
-        }
-      } else {
-        return /* false */0;
-      }
-    } else if (e2) {
-      return /* false */0;
-    } else {
-      return /* true */1;
-    }
-  };
-}
-
-function cardinal(param) {
-  if (param) {
-    return (cardinal(param[0]) + 1 | 0) + cardinal(param[3]) | 0;
-  } else {
-    return 0;
-  }
-}
-
-function bindings_aux(_accu, _param) {
-  while(true) {
-    var param = _param;
-    var accu = _accu;
-    if (param) {
-      _param = param[0];
-      _accu = /* :: */[
-        /* tuple */[
-          param[1],
-          param[2]
-        ],
-        bindings_aux(accu, param[3])
-      ];
-      continue ;
-      
-    } else {
-      return accu;
-    }
-  };
-}
-
-function bindings(s) {
-  return bindings_aux(/* [] */0, s);
-}
-
-var ObjectDict = [
-  /* Empty */0,
-  is_empty,
-  mem,
-  add,
-  singleton,
-  remove,
-  merge,
-  compare,
-  equal,
-  iter,
-  fold,
-  for_all,
-  exists,
-  filter,
-  partition,
-  cardinal,
-  bindings,
-  min_binding,
-  max_binding,
-  min_binding,
-  split,
-  find,
-  map,
-  mapi
-];
-
 var ParseFail = Caml_exceptions.create("Tea_json.Decoder.ParseFail");
 
 var string = /* Decoder */[(function (value) {
@@ -784,7 +105,7 @@ function list(param) {
                   }
                 };
                 try {
-                  return /* Ok */Block.__(0, [List.map(parse, $$Array.to_list(match[0]))]);
+                  return /* Ok */Block.__(0, [Belt_List.map(Belt_List.fromArray(match[0]), parse)]);
                 }
                 catch (raw_exn){
                   var exn = Js_exn.internalToOCamlException(raw_exn);
@@ -819,7 +140,7 @@ function array(param) {
                   }
                 };
                 try {
-                  return /* Ok */Block.__(0, [$$Array.map(parse, match[0])]);
+                  return /* Ok */Block.__(0, [Belt_Array.map(match[0], parse)]);
                 }
                 catch (raw_exn){
                   var exn = Js_exn.internalToOCamlException(raw_exn);
@@ -844,7 +165,7 @@ function keyValuePairs(param) {
               } else if (match.tag === 2) {
                 var o = match[0];
                 var keys = Object.keys(o);
-                var parse = function (k, l) {
+                var parse = function (l, k) {
                   var match = o[k];
                   if (match !== undefined) {
                     var match$1 = Curry._1(decoder, match);
@@ -870,7 +191,7 @@ function keyValuePairs(param) {
                   }
                 };
                 try {
-                  return /* Ok */Block.__(0, [$$Array.fold_right(parse, keys, /* [] */0)]);
+                  return /* Ok */Block.__(0, [Belt_Array.reduceReverse(keys, /* [] */0, parse)]);
                 }
                 catch (raw_exn){
                   var exn = Js_exn.internalToOCamlException(raw_exn);
@@ -895,7 +216,7 @@ function dict(param) {
               } else if (match.tag === 2) {
                 var o = match[0];
                 var keys = Object.keys(o);
-                var parse = function (k, d) {
+                var parse = function (d, k) {
                   var match = o[k];
                   if (match !== undefined) {
                     var match$1 = Curry._1(decoder, match);
@@ -905,7 +226,7 @@ function dict(param) {
                             match$1[0]
                           ];
                     } else {
-                      return add(k, match$1[0], d);
+                      return Belt_MapString.set(d, k, match$1[0]);
                     }
                   } else {
                     throw [
@@ -915,7 +236,7 @@ function dict(param) {
                   }
                 };
                 try {
-                  return /* Ok */Block.__(0, [$$Array.fold_right(parse, keys, /* Empty */0)]);
+                  return /* Ok */Block.__(0, [Belt_Array.reduceReverse(keys, Belt_MapString.empty, parse)]);
                 }
                 catch (raw_exn){
                   var exn = Js_exn.internalToOCamlException(raw_exn);
@@ -956,7 +277,9 @@ function field(key, param) {
 }
 
 function at(fields, dec) {
-  return List.fold_right(field, fields, dec);
+  return Belt_List.reduceReverseU(fields, dec, (function (d, k) {
+                return field(k, d);
+              }));
 }
 
 function index(idx, param) {
@@ -968,9 +291,9 @@ function index(idx, param) {
               } else if (match.tag === 3) {
                 var a = match[0];
                 if (idx < 0 || idx > a.length) {
-                  return /* Error */Block.__(1, ["Array index out of range: " + idx]);
+                  return /* Error */Block.__(1, ["Array index out of range: " + String(idx)]);
                 } else {
-                  return Curry._1(decoder, Caml_array.caml_array_get(a, idx));
+                  return Curry._1(decoder, a[idx]);
                 }
               } else {
                 return /* Error */Block.__(1, ["Non-array value"]);
@@ -1019,7 +342,7 @@ function oneOf(decoders) {
             })];
 }
 
-function map$1(mapper, param) {
+function map(mapper, param) {
   var decoder1 = param[0];
   return /* Decoder */[(function (value) {
               var match = Curry._1(decoder1, value);
@@ -1038,9 +361,7 @@ function map2(mapper, param, param$1) {
               var match = Curry._1(decoder1, value);
               var match$1 = Curry._1(decoder2, value);
               var exit = 0;
-              if (match.tag) {
-                exit = 1;
-              } else if (match$1.tag) {
+              if (match.tag || match$1.tag) {
                 exit = 1;
               } else {
                 return /* Ok */Block.__(0, [Curry._2(mapper, match[0], match$1[0])]);
@@ -1069,11 +390,7 @@ function map3(mapper, param, param$1, param$2) {
               var match$1 = Curry._1(decoder2, value);
               var match$2 = Curry._1(decoder3, value);
               var exit = 0;
-              if (match.tag) {
-                exit = 1;
-              } else if (match$1.tag) {
-                exit = 1;
-              } else if (match$2.tag) {
+              if (match.tag || match$1.tag || match$2.tag) {
                 exit = 1;
               } else {
                 return /* Ok */Block.__(0, [Curry._3(mapper, match[0], match$1[0], match$2[0])]);
@@ -1104,13 +421,7 @@ function map4(mapper, param, param$1, param$2, param$3) {
               var match$2 = Curry._1(decoder3, value);
               var match$3 = Curry._1(decoder4, value);
               var exit = 0;
-              if (match.tag) {
-                exit = 1;
-              } else if (match$1.tag) {
-                exit = 1;
-              } else if (match$2.tag) {
-                exit = 1;
-              } else if (match$3.tag) {
+              if (match.tag || match$1.tag || match$2.tag || match$3.tag) {
                 exit = 1;
               } else {
                 return /* Ok */Block.__(0, [Curry._4(mapper, match[0], match$1[0], match$2[0], match$3[0])]);
@@ -1143,15 +454,7 @@ function map5(mapper, param, param$1, param$2, param$3, param$4) {
               var match$3 = Curry._1(decoder4, value);
               var match$4 = Curry._1(decoder5, value);
               var exit = 0;
-              if (match.tag) {
-                exit = 1;
-              } else if (match$1.tag) {
-                exit = 1;
-              } else if (match$2.tag) {
-                exit = 1;
-              } else if (match$3.tag) {
-                exit = 1;
-              } else if (match$4.tag) {
+              if (match.tag || match$1.tag || match$2.tag || match$3.tag || match$4.tag) {
                 exit = 1;
               } else {
                 return /* Ok */Block.__(0, [Curry._5(mapper, match[0], match$1[0], match$2[0], match$3[0], match$4[0])]);
@@ -1186,17 +489,7 @@ function map6(mapper, param, param$1, param$2, param$3, param$4, param$5) {
               var match$4 = Curry._1(decoder5, value);
               var match$5 = Curry._1(decoder6, value);
               var exit = 0;
-              if (match.tag) {
-                exit = 1;
-              } else if (match$1.tag) {
-                exit = 1;
-              } else if (match$2.tag) {
-                exit = 1;
-              } else if (match$3.tag) {
-                exit = 1;
-              } else if (match$4.tag) {
-                exit = 1;
-              } else if (match$5.tag) {
+              if (match.tag || match$1.tag || match$2.tag || match$3.tag || match$4.tag || match$5.tag) {
                 exit = 1;
               } else {
                 return /* Ok */Block.__(0, [Curry._6(mapper, match[0], match$1[0], match$2[0], match$3[0], match$4[0], match$5[0])]);
@@ -1233,19 +526,7 @@ function map7(mapper, param, param$1, param$2, param$3, param$4, param$5, param$
               var match$5 = Curry._1(decoder6, value);
               var match$6 = Curry._1(decoder7, value);
               var exit = 0;
-              if (match.tag) {
-                exit = 1;
-              } else if (match$1.tag) {
-                exit = 1;
-              } else if (match$2.tag) {
-                exit = 1;
-              } else if (match$3.tag) {
-                exit = 1;
-              } else if (match$4.tag) {
-                exit = 1;
-              } else if (match$5.tag) {
-                exit = 1;
-              } else if (match$6.tag) {
+              if (match.tag || match$1.tag || match$2.tag || match$3.tag || match$4.tag || match$5.tag || match$6.tag) {
                 exit = 1;
               } else {
                 return /* Ok */Block.__(0, [Curry._7(mapper, match[0], match$1[0], match$2[0], match$3[0], match$4[0], match$5[0], match$6[0])]);
@@ -1284,21 +565,7 @@ function map8(mapper, param, param$1, param$2, param$3, param$4, param$5, param$
               var match$6 = Curry._1(decoder7, value);
               var match$7 = Curry._1(decoder8, value);
               var exit = 0;
-              if (match.tag) {
-                exit = 1;
-              } else if (match$1.tag) {
-                exit = 1;
-              } else if (match$2.tag) {
-                exit = 1;
-              } else if (match$3.tag) {
-                exit = 1;
-              } else if (match$4.tag) {
-                exit = 1;
-              } else if (match$5.tag) {
-                exit = 1;
-              } else if (match$6.tag) {
-                exit = 1;
-              } else if (match$7.tag) {
+              if (match.tag || match$1.tag || match$2.tag || match$3.tag || match$4.tag || match$5.tag || match$6.tag || match$7.tag) {
                 exit = 1;
               } else {
                 return /* Ok */Block.__(0, [Curry._8(mapper, match[0], match$1[0], match$2[0], match$3[0], match$4[0], match$5[0], match$6[0], match$7[0])]);
@@ -1357,7 +624,7 @@ function nullable(decoder) {
   return oneOf(/* :: */[
               $$null(/* None */0),
               /* :: */[
-                map$1((function (v) {
+                map((function (v) {
                         return /* Some */[v];
                       }), decoder),
                 /* [] */0
@@ -1404,7 +671,7 @@ function decodeString(decoder, string) {
 }
 
 var Decoder = /* module */[
-  /* ObjectDict */ObjectDict,
+  /* ObjectDict */0,
   /* ParseFail */ParseFail,
   /* string */string,
   /* int */$$int,
@@ -1420,7 +687,7 @@ var Decoder = /* module */[
   /* index */index,
   /* maybe */maybe,
   /* oneOf */oneOf,
-  /* map */map$1,
+  /* map */map,
   /* map2 */map2,
   /* map3 */map3,
   /* map4 */map4,
@@ -1468,7 +735,7 @@ function object_(v) {
     o[param[0]] = param[1];
     return o;
   };
-  return List.fold_left(aux, { }, v);
+  return Belt_List.reduce(v, { }, aux);
 }
 
 function array$1(v) {
diff --git a/lib/js/src/tea_mouse.js b/lib/js/src/tea_mouse.js
index 0228b36..64b3245 100644
--- a/lib/js/src/tea_mouse.js
+++ b/lib/js/src/tea_mouse.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 var Vdom = require("./vdom.js");
diff --git a/lib/js/src/tea_navigation.js b/lib/js/src/tea_navigation.js
index 42b0e95..7c507d5 100644
--- a/lib/js/src/tea_navigation.js
+++ b/lib/js/src/tea_navigation.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 var Block = require("bs-platform/lib/js/block.js");
diff --git a/lib/js/src/tea_program.js b/lib/js/src/tea_program.js
index f88b52e..7f4dc0c 100644
--- a/lib/js/src/tea_program.js
+++ b/lib/js/src/tea_program.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 var Curry = require("bs-platform/lib/js/curry.js");
diff --git a/lib/js/src/tea_random.js b/lib/js/src/tea_random.js
index 23906b3..47f3c2e 100644
--- a/lib/js/src/tea_random.js
+++ b/lib/js/src/tea_random.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 var Block = require("bs-platform/lib/js/block.js");
@@ -8,6 +8,10 @@ var Pervasives = require("bs-platform/lib/js/pervasives.js");
 
 Random.self_init(/* () */0);
 
+var minFloat = Number.MIN_VALUE;
+
+var maxFloat = Number.MAX_VALUE;
+
 var bool = /* Generator */[(function (state) {
       return Random.State[/* bool */9](state);
     })];
@@ -151,10 +155,6 @@ var minInt = Pervasives.min_int;
 
 var maxInt = Pervasives.max_int;
 
-var minFloat = Pervasives.min_float;
-
-var maxFloat = Pervasives.max_float;
-
 exports.minInt = minInt;
 exports.maxInt = maxInt;
 exports.minFloat = minFloat;
diff --git a/lib/js/src/tea_result.js b/lib/js/src/tea_result.js
index cc09796..3d17f78 100644
--- a/lib/js/src/tea_result.js
+++ b/lib/js/src/tea_result.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 var Block = require("bs-platform/lib/js/block.js");
@@ -42,14 +42,10 @@ function last_of(_param) {
     if (param) {
       var tl = param[1];
       var last = param[0];
-      if (tl) {
-        if (last.tag) {
-          return last;
-        } else {
-          _param = tl;
-          continue ;
-          
-        }
+      if (tl && !last.tag) {
+        _param = tl;
+        continue ;
+        
       } else {
         return last;
       }
diff --git a/lib/js/src/tea_sub.js b/lib/js/src/tea_sub.js
index 0d8ed6c..22827fc 100644
--- a/lib/js/src/tea_sub.js
+++ b/lib/js/src/tea_sub.js
@@ -1,9 +1,9 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
-var List = require("bs-platform/lib/js/list.js");
 var Block = require("bs-platform/lib/js/block.js");
 var Curry = require("bs-platform/lib/js/curry.js");
+var Belt_List = require("bs-platform/lib/js/belt_List.js");
 
 function batch(subs) {
   return /* Batch */Block.__(0, [subs]);
@@ -50,11 +50,11 @@ function run(oldCallbacks, newCallbacks, oldSub, newSub) {
           case 0 : 
               var subs = param[0];
               if (subs) {
-                return List.iter((function(callbacks){
+                return Belt_List.forEach(subs, (function(callbacks){
                           return function (param) {
                             return enable(callbacks, param);
                           }
-                          }(callbacks)), subs);
+                          }(callbacks)));
               } else {
                 return /* () */0;
               }
@@ -82,11 +82,11 @@ function run(oldCallbacks, newCallbacks, oldSub, newSub) {
           case 0 : 
               var subs = param[0];
               if (subs) {
-                return List.iter((function(callbacks){
+                return Belt_List.forEach(subs, (function(callbacks){
                           return function (param) {
                             return disable(callbacks, param);
                           }
-                          }(callbacks)), subs);
+                          }(callbacks)));
               } else {
                 return /* () */0;
               }
@@ -119,9 +119,7 @@ function run(oldCallbacks, newCallbacks, oldSub, newSub) {
   } else {
     switch (oldSub.tag | 0) {
       case 0 : 
-          if (typeof newSub === "number") {
-            exit = 1;
-          } else if (newSub.tag) {
+          if (typeof newSub === "number" || newSub.tag) {
             exit = 1;
           } else {
             var aux = function (_oldList, _newList) {
@@ -160,29 +158,21 @@ function run(oldCallbacks, newCallbacks, oldSub, newSub) {
           }
           break;
       case 1 : 
-          if (typeof newSub === "number") {
+          if (typeof newSub === "number" || !(newSub.tag === 1 && oldSub[0] === newSub[0])) {
             exit = 1;
-          } else if (newSub.tag === 1) {
-            if (oldSub[0] === newSub[0]) {
-              newSub[2][0] = oldSub[2][0];
-              return newSub;
-            } else {
-              exit = 1;
-            }
           } else {
-            exit = 1;
+            newSub[2][0] = oldSub[2][0];
+            return newSub;
           }
           break;
       case 2 : 
-          if (typeof newSub === "number") {
+          if (typeof newSub === "number" || newSub.tag !== 2) {
             exit = 1;
-          } else if (newSub.tag === 2) {
+          } else {
             var olderCallbacks = Curry._1(oldSub[0], oldCallbacks);
             var newerCallbacks = Curry._1(newSub[0], newCallbacks);
             run(olderCallbacks, newerCallbacks, oldSub[1], newSub[1]);
             return newSub;
-          } else {
-            exit = 1;
           }
           break;
       
diff --git a/lib/js/src/tea_svg.js b/lib/js/src/tea_svg.js
index a24631d..266fc84 100644
--- a/lib/js/src/tea_svg.js
+++ b/lib/js/src/tea_svg.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 var Vdom = require("./vdom.js");
diff --git a/lib/js/src/tea_svg_attributes.js b/lib/js/src/tea_svg_attributes.js
index 002be87..ed9212a 100644
--- a/lib/js/src/tea_svg_attributes.js
+++ b/lib/js/src/tea_svg_attributes.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 var Block = require("bs-platform/lib/js/block.js");
diff --git a/lib/js/src/tea_svg_events.js b/lib/js/src/tea_svg_events.js
index 3adeee6..8767a68 100644
--- a/lib/js/src/tea_svg_events.js
+++ b/lib/js/src/tea_svg_events.js
@@ -1,2 +1,2 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 /* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/src/tea_task.js b/lib/js/src/tea_task.js
index b5cd0e9..406c1e7 100644
--- a/lib/js/src/tea_task.js
+++ b/lib/js/src/tea_task.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 var Block = require("bs-platform/lib/js/block.js");
@@ -261,7 +261,7 @@ function testing() {
           })]);
   doTest(/* Ok */Block.__(0, [4]), a1);
   var a2 = andThen((function (n) {
-          var value = "" + n;
+          var value = String(n);
           return /* Task */[(function (cb) {
                       return Curry._1(cb, /* Ok */Block.__(0, [value]));
                     })];
@@ -283,7 +283,9 @@ function testing() {
             return Curry._1(cb, /* Ok */Block.__(0, [3]));
           })]);
   doTest(/* Ok */Block.__(0, [12]), m2);
-  var m3 = map(Pervasives.string_of_int, /* Task */[(function (cb) {
+  var m3 = map((function (prim) {
+          return String(prim);
+        }), /* Task */[(function (cb) {
             return Curry._1(cb, /* Ok */Block.__(0, [9]));
           })]);
   doTest(/* Ok */Block.__(0, ["9"]), m3);
@@ -337,7 +339,9 @@ function testing() {
           })]);
   doTest(/* Error */Block.__(1, [42]), e1);
   var n0 = sequence(/* :: */[
-        mapError(Pervasives.string_of_int, /* Task */[(function (cb) {
+        mapError((function (prim) {
+                return String(prim);
+              }), /* Task */[(function (cb) {
                   return Curry._1(cb, /* Error */Block.__(1, [42]));
                 })]),
         /* :: */[
@@ -349,7 +353,9 @@ function testing() {
       ]);
   doTest(/* Error */Block.__(1, ["42"]), n0);
   var n1 = sequence(/* :: */[
-        mapError(Pervasives.string_of_int, /* Task */[(function (cb) {
+        mapError((function (prim) {
+                return String(prim);
+              }), /* Task */[(function (cb) {
                   return Curry._1(cb, /* Ok */Block.__(0, [1]));
                 })]),
         /* :: */[
@@ -361,7 +367,9 @@ function testing() {
       ]);
   doTest(/* Error */Block.__(1, ["3.14"]), n1);
   var n2 = sequence(/* :: */[
-        mapError(Pervasives.string_of_int, /* Task */[(function (cb) {
+        mapError((function (prim) {
+                return String(prim);
+              }), /* Task */[(function (cb) {
                   return Curry._1(cb, /* Ok */Block.__(0, [1]));
                 })]),
         /* :: */[
diff --git a/lib/js/src/tea_time.js b/lib/js/src/tea_time.js
index 621f78e..4d12699 100644
--- a/lib/js/src/tea_time.js
+++ b/lib/js/src/tea_time.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 var Block = require("bs-platform/lib/js/block.js");
diff --git a/lib/js/src/vdom.js b/lib/js/src/vdom.js
index ea7e38a..8becdb9 100644
--- a/lib/js/src/vdom.js
+++ b/lib/js/src/vdom.js
@@ -1,13 +1,12 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
-var List = require("bs-platform/lib/js/list.js");
 var Block = require("bs-platform/lib/js/block.js");
 var Curry = require("bs-platform/lib/js/curry.js");
 var $$String = require("bs-platform/lib/js/string.js");
 var Caml_obj = require("bs-platform/lib/js/caml_obj.js");
 var Web_node = require("./web_node.js");
-var Caml_array = require("bs-platform/lib/js/caml_array.js");
+var Belt_List = require("bs-platform/lib/js/belt_List.js");
 var Web_document = require("./web_document.js");
 var Caml_builtin_exceptions = require("bs-platform/lib/js/caml_builtin_exceptions.js");
 
@@ -122,7 +121,7 @@ function renderToHtmlString(_param) {
                           /* :: */[
                             tagName,
                             /* :: */[
-                              $$String.concat("", List.map((function (p) {
+                              $$String.concat("", Belt_List.mapU(param[4], (function (p) {
                                           var param = p;
                                           if (typeof param === "number") {
                                             return "";
@@ -185,7 +184,7 @@ function renderToHtmlString(_param) {
                                                   return $$String.concat("", /* :: */[
                                                               " style=\"",
                                                               /* :: */[
-                                                                $$String.concat(";", List.map((function (param) {
+                                                                $$String.concat(";", Belt_List.mapU(param[0], (function (param) {
                                                                             return $$String.concat("", /* :: */[
                                                                                         param[0],
                                                                                         /* :: */[
@@ -199,7 +198,7 @@ function renderToHtmlString(_param) {
                                                                                           ]
                                                                                         ]
                                                                                       ]);
-                                                                          }), param[0])),
+                                                                          }))),
                                                                 /* :: */[
                                                                   "\"",
                                                                   /* [] */0
@@ -209,11 +208,11 @@ function renderToHtmlString(_param) {
                                               
                                             }
                                           }
-                                        }), param[4])),
+                                        }))),
                               /* :: */[
                                 ">",
                                 /* :: */[
-                                  $$String.concat("", List.map(renderToHtmlString, param[5])),
+                                  $$String.concat("", Belt_List.mapU(param[5], renderToHtmlString)),
                                   /* :: */[
                                     "</",
                                     /* :: */[
@@ -352,9 +351,9 @@ function patchVNodesOnElems_PropertiesApply_Add(callbacks, elem, _, param) {
           param[2][0] = eventHandler_Register(callbacks, elem, param[0], param[1]);
           return /* () */0;
       case 4 : 
-          return List.fold_left((function (_, param) {
+          return Belt_List.reduceU(param[0], /* () */0, (function (_, param) {
                         return Web_node.setStyleProperty(elem, /* None */0, param[0], param[1]);
-                      }), /* () */0, param[0]);
+                      }));
       
     }
   }
@@ -385,9 +384,9 @@ function patchVNodesOnElems_PropertiesApply_Remove(_, elem, _$1, param) {
           cache[0] = eventHandler_Unregister(elem, param[0], cache[0]);
           return /* () */0;
       case 4 : 
-          return List.fold_left((function (_, param) {
+          return Belt_List.reduceU(param[0], /* () */0, (function (_, param) {
                         return Web_node.setStyleProperty(elem, /* None */0, param[0], null);
-                      }), /* () */0, param[0]);
+                      }));
       
     }
   }
@@ -434,7 +433,7 @@ function patchVNodesOnElems_PropertiesApply_Mutate(_, elem, _$1, oldProp, _newPr
                   "Passed a non-Style to a new Style as a Mutations while the old Style is not actually a style!"
                 ];
           } else if (oldProp.tag === 4) {
-            return List.fold_left2((function (_, param, param$1) {
+            return Belt_List.reduce2U(oldProp[0], _newProp[0], /* () */0, (function (_, param, param$1) {
                           var nv = param$1[1];
                           var nk = param$1[0];
                           var ok = param[0];
@@ -448,14 +447,13 @@ function patchVNodesOnElems_PropertiesApply_Mutate(_, elem, _$1, oldProp, _newPr
                             Web_node.setStyleProperty(elem, /* None */0, ok, null);
                             return Web_node.setStyleProperty(elem, /* None */0, nk, nv);
                           }
-                        }), /* () */0, oldProp[0], _newProp[0]);
+                        }));
           } else {
             throw [
                   Caml_builtin_exceptions.failure,
                   "Passed a non-Style to a new Style as a Mutations while the old Style is not actually a style!"
                 ];
           }
-          break;
       
     }
   }
@@ -484,9 +482,7 @@ function patchVNodesOnElems_PropertiesApply(callbacks, elem, _idx, _oldPropertie
           switch (_oldProp.tag | 0) {
             case 0 : 
                 var newProp = newProperties[0];
-                if (typeof newProp === "number") {
-                  exit = 1;
-                } else if (newProp.tag) {
+                if (typeof newProp === "number" || newProp.tag) {
                   exit = 1;
                 } else {
                   if (!(_oldProp[0] === newProp[0] && _oldProp[1] === newProp[1])) {
@@ -501,9 +497,9 @@ function patchVNodesOnElems_PropertiesApply(callbacks, elem, _idx, _oldPropertie
                 break;
             case 1 : 
                 var newProp$1 = newProperties[0];
-                if (typeof newProp$1 === "number") {
+                if (typeof newProp$1 === "number" || newProp$1.tag !== 1) {
                   exit = 1;
-                } else if (newProp$1.tag === 1) {
+                } else {
                   if (!(_oldProp[0] === newProp$1[0] && _oldProp[1] === newProp$1[1] && _oldProp[2] === newProp$1[2])) {
                     patchVNodesOnElems_PropertiesApply_Mutate(callbacks, elem, idx, _oldProp, newProp$1);
                   }
@@ -512,15 +508,13 @@ function patchVNodesOnElems_PropertiesApply(callbacks, elem, _idx, _oldPropertie
                   _idx = idx + 1 | 0;
                   continue ;
                   
-                } else {
-                  exit = 1;
                 }
                 break;
             case 2 : 
                 var newProp$2 = newProperties[0];
-                if (typeof newProp$2 === "number") {
+                if (typeof newProp$2 === "number" || newProp$2.tag !== 2) {
                   exit = 1;
-                } else if (newProp$2.tag === 2) {
+                } else {
                   if (!(_oldProp[0] === newProp$2[0] && _oldProp[1] === newProp$2[1])) {
                     patchVNodesOnElems_PropertiesApply_Mutate(callbacks, elem, idx, _oldProp, newProp$2);
                   }
@@ -529,30 +523,26 @@ function patchVNodesOnElems_PropertiesApply(callbacks, elem, _idx, _oldPropertie
                   _idx = idx + 1 | 0;
                   continue ;
                   
-                } else {
-                  exit = 1;
                 }
                 break;
             case 3 : 
                 var _newProp = newProperties[0];
-                if (typeof _newProp === "number") {
+                if (typeof _newProp === "number" || _newProp.tag !== 3) {
                   exit = 1;
-                } else if (_newProp.tag === 3) {
+                } else {
                   eventHandler_Mutate(callbacks, elem, _oldProp[0], _newProp[0], _oldProp[1], _newProp[1], _oldProp[2], _newProp[2]);
                   _newProperties = newProperties[1];
                   _oldProperties = oldProperties[1];
                   _idx = idx + 1 | 0;
                   continue ;
                   
-                } else {
-                  exit = 1;
                 }
                 break;
             case 4 : 
                 var newProp$3 = newProperties[0];
-                if (typeof newProp$3 === "number") {
+                if (typeof newProp$3 === "number" || newProp$3.tag !== 4) {
                   exit = 1;
-                } else if (newProp$3.tag === 4) {
+                } else {
                   if (!Caml_obj.caml_equal(_oldProp[0], newProp$3[0])) {
                     patchVNodesOnElems_PropertiesApply_Mutate(callbacks, elem, idx, _oldProp, newProp$3);
                   }
@@ -561,8 +551,6 @@ function patchVNodesOnElems_PropertiesApply(callbacks, elem, _idx, _oldPropertie
                   _idx = idx + 1 | 0;
                   continue ;
                   
-                } else {
-                  exit = 1;
                 }
                 break;
             
@@ -613,19 +601,19 @@ function genEmptyProps(length) {
 }
 
 function mapEmptyProps(props) {
-  return List.map((function () {
+  return Belt_List.mapU(props, (function () {
                 return /* NoProp */0;
-              }), props);
+              }));
 }
 
 function patchVNodesOnElems_ReplaceNode(callbacks, elem, elems, idx, param) {
   if (param.tag === 2) {
     var newProperties = param[4];
-    var oldChild = Caml_array.caml_array_get(elems, idx);
+    var oldChild = elems[idx];
     var newChild = Web_document.createElementNsOptional(param[0], param[1]);
-    var match = patchVNodesOnElems_Properties(callbacks, newChild, List.map((function () {
+    var match = patchVNodesOnElems_Properties(callbacks, newChild, Belt_List.mapU(newProperties, (function () {
                 return /* NoProp */0;
-              }), newProperties), newProperties);
+              })), newProperties);
     if (match !== 0) {
       var childChildren = newChild.childNodes;
       patchVNodesOnElems(callbacks, newChild, childChildren, 0, /* [] */0, param[5]);
@@ -664,9 +652,9 @@ function patchVNodesOnElems_CreateElement(_callbacks, _param) {
       case 2 : 
           var newProperties = param[4];
           var newChild = Web_document.createElementNsOptional(param[0], param[1]);
-          var match = patchVNodesOnElems_Properties(callbacks, newChild, List.map((function () {
+          var match = patchVNodesOnElems_Properties(callbacks, newChild, Belt_List.mapU(newProperties, (function () {
                       return /* NoProp */0;
-                    }), newProperties), newProperties);
+                    })), newProperties);
           if (match !== 0) {
             var childChildren = newChild.childNodes;
             patchVNodesOnElems(callbacks, newChild, childChildren, 0, /* [] */0, param[5]);
@@ -681,7 +669,6 @@ function patchVNodesOnElems_CreateElement(_callbacks, _param) {
                   ]
                 ];
           }
-          break;
       case 3 : 
           var vdom = Curry._1(param[1], /* () */0);
           param[2][0] = vdom;
@@ -702,7 +689,7 @@ function patchVNodesOnElems_MutateNode(callbacks, elem, elems, idx, oldNode, new
       if (oldNode[3] !== newNode[3] || oldNode[1] !== newNode[1]) {
         return patchVNodesOnElems_ReplaceNode(callbacks, elem, elems, idx, newNode);
       } else {
-        var child = Caml_array.caml_array_get(elems, idx);
+        var child = elems[idx];
         var childChildren = child.childNodes;
         if (!patchVNodesOnElems_Properties(callbacks, child, oldNode[4], newNode[4])) {
           console.log("VDom:  Failed swapping properties because the property list length changed, use `noProp` to swap properties instead, not by altering the list structure.  This is a massive inefficiency until this issue is resolved.");
@@ -736,16 +723,14 @@ function patchVNodesOnElems(callbacks, elem, elems, _idx, _oldVNodes, _newVNodes
         case 0 : 
             if (newVNodes) {
               var match = newVNodes[0];
-              if (match.tag) {
+              if (match.tag || oldNode[0] !== match[0]) {
                 exit = 1;
-              } else if (oldNode[0] === match[0]) {
+              } else {
                 _newVNodes = newVNodes[1];
                 _oldVNodes = oldVNodes[1];
                 _idx = idx + 1 | 0;
                 continue ;
                 
-              } else {
-                exit = 1;
               }
             } else {
               exit = 1;
@@ -757,7 +742,7 @@ function patchVNodesOnElems(callbacks, elem, elems, _idx, _oldVNodes, _newVNodes
               if (match$1.tag === 1) {
                 var newText = match$1[0];
                 if (oldNode[0] !== newText) {
-                  var child = Caml_array.caml_array_get(elems, idx);
+                  var child = elems[idx];
                   child.nodeValue = newText;
                 }
                 _newVNodes = newVNodes[1];
@@ -810,20 +795,16 @@ function patchVNodesOnElems(callbacks, elem, elems, _idx, _oldVNodes, _newVNodes
                       var exit$3 = 0;
                       if (newRest) {
                         var match$3 = newRest[0];
-                        if (match$3.tag === 2) {
-                          if (olderNamespace === newNamespace && olderTagName === newTagName && olderKey === newKey && oldNamespace === match$3[0] && oldTagName === match$3[1] && oldKey === match$3[2]) {
-                            var firstChild = Caml_array.caml_array_get(elems, idx);
-                            var secondChild = Caml_array.caml_array_get(elems, idx + 1 | 0);
-                            elem.removeChild(secondChild);
-                            Web_node.insertBefore(elem, secondChild, firstChild);
-                            _newVNodes = newRest[1];
-                            _oldVNodes = olderRest;
-                            _idx = idx + 2 | 0;
-                            continue ;
-                            
-                          } else {
-                            exit$3 = 4;
-                          }
+                        if (match$3.tag === 2 && olderNamespace === newNamespace && olderTagName === newTagName && olderKey === newKey && oldNamespace === match$3[0] && oldTagName === match$3[1] && oldKey === match$3[2]) {
+                          var firstChild = elems[idx];
+                          var secondChild = elems[idx + 1 | 0];
+                          elem.removeChild(secondChild);
+                          Web_node.insertBefore(elem, secondChild, firstChild);
+                          _newVNodes = newRest[1];
+                          _oldVNodes = olderRest;
+                          _idx = idx + 2 | 0;
+                          continue ;
+                          
                         } else {
                           exit$3 = 4;
                         }
@@ -832,7 +813,7 @@ function patchVNodesOnElems(callbacks, elem, elems, _idx, _oldVNodes, _newVNodes
                       }
                       if (exit$3 === 4) {
                         if (olderNamespace === newNamespace && olderTagName === newTagName && olderKey === newKey) {
-                          var oldChild = Caml_array.caml_array_get(elems, idx);
+                          var oldChild = elems[idx];
                           elem.removeChild(oldChild);
                           _newVNodes = newRest;
                           _oldVNodes = olderRest;
@@ -853,18 +834,14 @@ function patchVNodesOnElems(callbacks, elem, elems, _idx, _oldVNodes, _newVNodes
                   if (exit$2 === 3) {
                     if (newRest) {
                       var match$4 = newRest[0];
-                      if (match$4.tag === 2) {
-                        if (oldNamespace === match$4[0] && oldTagName === match$4[1] && oldKey === match$4[2]) {
-                          var oldChild$1 = Caml_array.caml_array_get(elems, idx);
-                          var newChild = patchVNodesOnElems_CreateElement(callbacks, newNode);
-                          Web_node.insertBefore(elem, newChild, oldChild$1);
-                          _newVNodes = newRest;
-                          _idx = idx + 1 | 0;
-                          continue ;
-                          
-                        } else {
-                          exit$1 = 2;
-                        }
+                      if (match$4.tag === 2 && oldNamespace === match$4[0] && oldTagName === match$4[1] && oldKey === match$4[2]) {
+                        var oldChild$1 = elems[idx];
+                        var newChild = patchVNodesOnElems_CreateElement(callbacks, newNode);
+                        Web_node.insertBefore(elem, newChild, oldChild$1);
+                        _newVNodes = newRest;
+                        _idx = idx + 1 | 0;
+                        continue ;
+                        
                       } else {
                         exit$1 = 2;
                       }
@@ -918,20 +895,16 @@ function patchVNodesOnElems(callbacks, elem, elems, _idx, _oldVNodes, _newVNodes
                       var exit$6 = 0;
                       if (newRest$1) {
                         var match$7 = newRest$1[0];
-                        if (match$7.tag === 3) {
-                          if (olderKey$1 === newKey$1 && oldKey$1 === match$7[0]) {
-                            var firstChild$1 = Caml_array.caml_array_get(elems, idx);
-                            var secondChild$1 = Caml_array.caml_array_get(elems, idx + 1 | 0);
-                            elem.removeChild(secondChild$1);
-                            Web_node.insertBefore(elem, secondChild$1, firstChild$1);
-                            _newVNodes = newRest$1[1];
-                            _oldVNodes = olderRest$1;
-                            _idx = idx + 2 | 0;
-                            continue ;
-                            
-                          } else {
-                            exit$6 = 4;
-                          }
+                        if (match$7.tag === 3 && olderKey$1 === newKey$1 && oldKey$1 === match$7[0]) {
+                          var firstChild$1 = elems[idx];
+                          var secondChild$1 = elems[idx + 1 | 0];
+                          elem.removeChild(secondChild$1);
+                          Web_node.insertBefore(elem, secondChild$1, firstChild$1);
+                          _newVNodes = newRest$1[1];
+                          _oldVNodes = olderRest$1;
+                          _idx = idx + 2 | 0;
+                          continue ;
+                          
                         } else {
                           exit$6 = 4;
                         }
@@ -940,7 +913,7 @@ function patchVNodesOnElems(callbacks, elem, elems, _idx, _oldVNodes, _newVNodes
                       }
                       if (exit$6 === 4) {
                         if (olderKey$1 === newKey$1) {
-                          var oldChild$2 = Caml_array.caml_array_get(elems, idx);
+                          var oldChild$2 = elems[idx];
                           elem.removeChild(oldChild$2);
                           var oldVdom = match$6[2][0];
                           newCache[0] = oldVdom;
@@ -963,20 +936,16 @@ function patchVNodesOnElems(callbacks, elem, elems, _idx, _oldVNodes, _newVNodes
                   if (exit$5 === 3) {
                     if (newRest$1) {
                       var match$8 = newRest$1[0];
-                      if (match$8.tag === 3) {
-                        if (match$8[0] === oldKey$1) {
-                          var oldChild$3 = Caml_array.caml_array_get(elems, idx);
-                          var newVdom = Curry._1(newGen, /* () */0);
-                          newCache[0] = newVdom;
-                          var newChild$1 = patchVNodesOnElems_CreateElement(callbacks, newVdom);
-                          Web_node.insertBefore(elem, newChild$1, oldChild$3);
-                          _newVNodes = newRest$1;
-                          _idx = idx + 1 | 0;
-                          continue ;
-                          
-                        } else {
-                          exit$4 = 2;
-                        }
+                      if (match$8.tag === 3 && match$8[0] === oldKey$1) {
+                        var oldChild$3 = elems[idx];
+                        var newVdom = Curry._1(newGen, /* () */0);
+                        newCache[0] = newVdom;
+                        var newChild$1 = patchVNodesOnElems_CreateElement(callbacks, newVdom);
+                        Web_node.insertBefore(elem, newChild$1, oldChild$3);
+                        _newVNodes = newRest$1;
+                        _idx = idx + 1 | 0;
+                        continue ;
+                        
                       } else {
                         exit$4 = 2;
                       }
@@ -1034,7 +1003,7 @@ function patchVNodesOnElems(callbacks, elem, elems, _idx, _oldVNodes, _newVNodes
             continue ;
             
           } else {
-            var oldChild$4 = Caml_array.caml_array_get(elems, idx);
+            var oldChild$4 = elems[idx];
             var newChild$2 = patchVNodesOnElems_CreateElement(callbacks, newNode$1);
             Web_node.insertBefore(elem, newChild$2, oldChild$4);
             elem.removeChild(oldChild$4);
@@ -1045,7 +1014,7 @@ function patchVNodesOnElems(callbacks, elem, elems, _idx, _oldVNodes, _newVNodes
             
           }
         } else {
-          var child$1 = Caml_array.caml_array_get(elems, idx);
+          var child$1 = elems[idx];
           elem.removeChild(child$1);
           _newVNodes = /* [] */0;
           _oldVNodes = oldRest$2;
diff --git a/lib/js/src/web.js b/lib/js/src/web.js
index 6b76110..5e7a467 100644
--- a/lib/js/src/web.js
+++ b/lib/js/src/web.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 
diff --git a/lib/js/src/web_date.js b/lib/js/src/web_date.js
index 2e6e380..343b257 100644
--- a/lib/js/src/web_date.js
+++ b/lib/js/src/web_date.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 
diff --git a/lib/js/src/web_document.js b/lib/js/src/web_document.js
index 8d00a5b..6d52410 100644
--- a/lib/js/src/web_document.js
+++ b/lib/js/src/web_document.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 
diff --git a/lib/js/src/web_event.js b/lib/js/src/web_event.js
index 3adeee6..8767a68 100644
--- a/lib/js/src/web_event.js
+++ b/lib/js/src/web_event.js
@@ -1,2 +1,2 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 /* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/src/web_formdata.js b/lib/js/src/web_formdata.js
index 1bded58..e1873a5 100644
--- a/lib/js/src/web_formdata.js
+++ b/lib/js/src/web_formdata.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 
diff --git a/lib/js/src/web_json.js b/lib/js/src/web_json.js
index dcb3f73..1a90573 100644
--- a/lib/js/src/web_json.js
+++ b/lib/js/src/web_json.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 var Js_json = require("bs-platform/lib/js/js_json.js");
diff --git a/lib/js/src/web_location.js b/lib/js/src/web_location.js
index 370882f..144164c 100644
--- a/lib/js/src/web_location.js
+++ b/lib/js/src/web_location.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 
@@ -7,7 +7,8 @@ function getHref($$location) {
 }
 
 function setHref($$location, value) {
-  return $$location.href = value;
+  $$location.href = value;
+  return /* () */0;
 }
 
 function getProtocol($$location) {
@@ -15,7 +16,8 @@ function getProtocol($$location) {
 }
 
 function setProtocol($$location, value) {
-  return $$location.protocol = value;
+  $$location.protocol = value;
+  return /* () */0;
 }
 
 function getHost($$location) {
@@ -23,7 +25,8 @@ function getHost($$location) {
 }
 
 function setHost($$location, value) {
-  return $$location.host = value;
+  $$location.host = value;
+  return /* () */0;
 }
 
 function getHostname($$location) {
@@ -31,7 +34,8 @@ function getHostname($$location) {
 }
 
 function setHostname($$location, value) {
-  return $$location.hostname = value;
+  $$location.hostname = value;
+  return /* () */0;
 }
 
 function getPort($$location) {
@@ -39,7 +43,8 @@ function getPort($$location) {
 }
 
 function setPort($$location, value) {
-  return $$location.port = value;
+  $$location.port = value;
+  return /* () */0;
 }
 
 function getPathname($$location) {
@@ -47,7 +52,8 @@ function getPathname($$location) {
 }
 
 function setPathname($$location, value) {
-  return $$location.pathname = value;
+  $$location.pathname = value;
+  return /* () */0;
 }
 
 function getSearch($$location) {
@@ -55,7 +61,8 @@ function getSearch($$location) {
 }
 
 function setSearch($$location, value) {
-  return $$location.search = value;
+  $$location.search = value;
+  return /* () */0;
 }
 
 function getHash($$location) {
@@ -63,7 +70,8 @@ function getHash($$location) {
 }
 
 function setHash($$location, value) {
-  return $$location.hash = value;
+  $$location.hash = value;
+  return /* () */0;
 }
 
 function getUsername($$location) {
@@ -71,7 +79,8 @@ function getUsername($$location) {
 }
 
 function setUsername($$location, value) {
-  return $$location.username = value;
+  $$location.username = value;
+  return /* () */0;
 }
 
 function getPassword($$location) {
@@ -79,7 +88,8 @@ function getPassword($$location) {
 }
 
 function setPassword($$location, value) {
-  return $$location.password = value;
+  $$location.password = value;
+  return /* () */0;
 }
 
 function getOrigin($$location) {
diff --git a/lib/js/src/web_node.js b/lib/js/src/web_node.js
index 6d16b99..f05dae6 100644
--- a/lib/js/src/web_node.js
+++ b/lib/js/src/web_node.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 
@@ -95,7 +95,8 @@ function focus(n) {
 }
 
 function set_nodeValue(n, text) {
-  return n.nodeValue = text;
+  n.nodeValue = text;
+  return /* () */0;
 }
 
 function get_nodeValue(n) {
diff --git a/lib/js/src/web_window.js b/lib/js/src/web_window.js
index f819143..5e130f8 100644
--- a/lib/js/src/web_window.js
+++ b/lib/js/src/web_window.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 
diff --git a/lib/js/src/web_window_history.js b/lib/js/src/web_window_history.js
index 30c04ca..2c9fb76 100644
--- a/lib/js/src/web_window_history.js
+++ b/lib/js/src/web_window_history.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 
diff --git a/lib/js/src/web_window_localstorage.js b/lib/js/src/web_window_localstorage.js
index 317222f..384c87f 100644
--- a/lib/js/src/web_window_localstorage.js
+++ b/lib/js/src/web_window_localstorage.js
@@ -1,4 +1,4 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
 
diff --git a/lib/js/src/web_xmlhttprequest.js b/lib/js/src/web_xmlhttprequest.js
index 1be7c00..01b0cbd 100644
--- a/lib/js/src/web_xmlhttprequest.js
+++ b/lib/js/src/web_xmlhttprequest.js
@@ -1,13 +1,12 @@
-// Generated by BUCKLESCRIPT VERSION 2.2.2, PLEASE EDIT WITH CARE
+// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE
 'use strict';
 
-var List = require("bs-platform/lib/js/list.js");
-var $$Array = require("bs-platform/lib/js/array.js");
 var Block = require("bs-platform/lib/js/block.js");
-var Curry = require("bs-platform/lib/js/curry.js");
+var Belt_List = require("bs-platform/lib/js/belt_List.js");
+var Belt_Array = require("bs-platform/lib/js/belt_Array.js");
 var Js_primitive = require("bs-platform/lib/js/js_primitive.js");
 var Web_formdata = require("./web_formdata.js");
-var Caml_primitive = require("bs-platform/lib/js/caml_primitive.js");
+var Belt_MapString = require("bs-platform/lib/js/belt_MapString.js");
 var Caml_builtin_exceptions = require("bs-platform/lib/js/caml_builtin_exceptions.js");
 
 function abort(x) {
@@ -32,7 +31,11 @@ function getAllResponseHeadersAsList(x) {
   if (err.tag) {
     return err;
   } else {
-    return /* Ok */Block.__(0, [List.map((function (param) {
+    return /* Ok */Block.__(0, [Belt_List.map(Belt_List.keep(Belt_List.fromArray(Belt_Array.map(err[0].split("\r\n"), (function (param) {
+                                  return param.split(": ", 2);
+                                }))), (function (a) {
+                          return +(a.length === 2);
+                        })), (function (param) {
                       if (param.length !== 2) {
                         throw [
                               Caml_builtin_exceptions.failure,
@@ -46,499 +49,19 @@ function getAllResponseHeadersAsList(x) {
                                 value
                               ];
                       }
-                    }), List.filter((function (a) {
-                            return +(a.length === 2);
-                          }))($$Array.to_list($$Array.map((function (param) {
-                                  return param.split(": ", 2);
-                                }), err[0].split("\r\n")))))]);
+                    }))]);
   }
 }
 
 function getAllResponseHeadersAsDict(x) {
-  var height = function (param) {
-    if (param) {
-      return param[4];
-    } else {
-      return 0;
-    }
-  };
-  var create = function (l, x, d, r) {
-    var hl = height(l);
-    var hr = height(r);
-    return /* Node */[
-            l,
-            x,
-            d,
-            r,
-            hl >= hr ? hl + 1 | 0 : hr + 1 | 0
-          ];
-  };
-  var singleton = function (x, d) {
-    return /* Node */[
-            /* Empty */0,
-            x,
-            d,
-            /* Empty */0,
-            1
-          ];
-  };
-  var bal = function (l, x, d, r) {
-    var hl = l ? l[4] : 0;
-    var hr = r ? r[4] : 0;
-    if (hl > (hr + 2 | 0)) {
-      if (l) {
-        var lr = l[3];
-        var ld = l[2];
-        var lv = l[1];
-        var ll = l[0];
-        if (height(ll) >= height(lr)) {
-          return create(ll, lv, ld, create(lr, x, d, r));
-        } else if (lr) {
-          return create(create(ll, lv, ld, lr[0]), lr[1], lr[2], create(lr[3], x, d, r));
-        } else {
-          throw [
-                Caml_builtin_exceptions.invalid_argument,
-                "Map.bal"
-              ];
-        }
-      } else {
-        throw [
-              Caml_builtin_exceptions.invalid_argument,
-              "Map.bal"
-            ];
-      }
-    } else if (hr > (hl + 2 | 0)) {
-      if (r) {
-        var rr = r[3];
-        var rd = r[2];
-        var rv = r[1];
-        var rl = r[0];
-        if (height(rr) >= height(rl)) {
-          return create(create(l, x, d, rl), rv, rd, rr);
-        } else if (rl) {
-          return create(create(l, x, d, rl[0]), rl[1], rl[2], create(rl[3], rv, rd, rr));
-        } else {
-          throw [
-                Caml_builtin_exceptions.invalid_argument,
-                "Map.bal"
-              ];
-        }
-      } else {
-        throw [
-              Caml_builtin_exceptions.invalid_argument,
-              "Map.bal"
-            ];
-      }
-    } else {
-      return /* Node */[
-              l,
-              x,
-              d,
-              r,
-              hl >= hr ? hl + 1 | 0 : hr + 1 | 0
-            ];
-    }
-  };
-  var add = function (x, data, param) {
-    if (param) {
-      var r = param[3];
-      var d = param[2];
-      var v = param[1];
-      var l = param[0];
-      var c = Caml_primitive.caml_string_compare(x, v);
-      if (c) {
-        if (c < 0) {
-          return bal(add(x, data, l), v, d, r);
-        } else {
-          return bal(l, v, d, add(x, data, r));
-        }
-      } else {
-        return /* Node */[
-                l,
-                x,
-                data,
-                r,
-                param[4]
-              ];
-      }
-    } else {
-      return /* Node */[
-              /* Empty */0,
-              x,
-              data,
-              /* Empty */0,
-              1
-            ];
-    }
-  };
-  var min_binding = function (_param) {
-    while(true) {
-      var param = _param;
-      if (param) {
-        var l = param[0];
-        if (l) {
-          _param = l;
-          continue ;
-          
-        } else {
-          return /* tuple */[
-                  param[1],
-                  param[2]
-                ];
-        }
-      } else {
-        throw Caml_builtin_exceptions.not_found;
-      }
-    };
-  };
-  var remove_min_binding = function (param) {
-    if (param) {
-      var l = param[0];
-      if (l) {
-        return bal(remove_min_binding(l), param[1], param[2], param[3]);
-      } else {
-        return param[3];
-      }
-    } else {
-      throw [
-            Caml_builtin_exceptions.invalid_argument,
-            "Map.remove_min_elt"
-          ];
-    }
-  };
-  var remove = function (x, param) {
-    if (param) {
-      var r = param[3];
-      var d = param[2];
-      var v = param[1];
-      var l = param[0];
-      var c = Caml_primitive.caml_string_compare(x, v);
-      if (c) {
-        if (c < 0) {
-          return bal(remove(x, l), v, d, r);
-        } else {
-          return bal(l, v, d, remove(x, r));
-        }
-      } else {
-        var t1 = l;
-        var t2 = r;
-        if (t1) {
-          if (t2) {
-            var match = min_binding(t2);
-            return bal(t1, match[0], match[1], remove_min_binding(t2));
-          } else {
-            return t1;
-          }
-        } else {
-          return t2;
-        }
-      }
-    } else {
-      return /* Empty */0;
-    }
-  };
-  var iter = function (f, _param) {
-    while(true) {
-      var param = _param;
-      if (param) {
-        iter(f, param[0]);
-        Curry._2(f, param[1], param[2]);
-        _param = param[3];
-        continue ;
-        
-      } else {
-        return /* () */0;
-      }
-    };
-  };
-  var map = function (f, param) {
-    if (param) {
-      var l$prime = map(f, param[0]);
-      var d$prime = Curry._1(f, param[2]);
-      var r$prime = map(f, param[3]);
-      return /* Node */[
-              l$prime,
-              param[1],
-              d$prime,
-              r$prime,
-              param[4]
-            ];
-    } else {
-      return /* Empty */0;
-    }
-  };
-  var mapi = function (f, param) {
-    if (param) {
-      var v = param[1];
-      var l$prime = mapi(f, param[0]);
-      var d$prime = Curry._2(f, v, param[2]);
-      var r$prime = mapi(f, param[3]);
-      return /* Node */[
-              l$prime,
-              v,
-              d$prime,
-              r$prime,
-              param[4]
-            ];
-    } else {
-      return /* Empty */0;
-    }
-  };
-  var fold = function (f, _m, _accu) {
-    while(true) {
-      var accu = _accu;
-      var m = _m;
-      if (m) {
-        _accu = Curry._3(f, m[1], m[2], fold(f, m[0], accu));
-        _m = m[3];
-        continue ;
-        
-      } else {
-        return accu;
-      }
-    };
-  };
-  var for_all = function (p, _param) {
-    while(true) {
-      var param = _param;
-      if (param) {
-        if (Curry._2(p, param[1], param[2])) {
-          if (for_all(p, param[0])) {
-            _param = param[3];
-            continue ;
-            
-          } else {
-            return /* false */0;
-          }
-        } else {
-          return /* false */0;
-        }
-      } else {
-        return /* true */1;
-      }
-    };
-  };
-  var exists = function (p, _param) {
-    while(true) {
-      var param = _param;
-      if (param) {
-        if (Curry._2(p, param[1], param[2])) {
-          return /* true */1;
-        } else if (exists(p, param[0])) {
-          return /* true */1;
-        } else {
-          _param = param[3];
-          continue ;
-          
-        }
-      } else {
-        return /* false */0;
-      }
-    };
-  };
-  var add_min_binding = function (k, v, param) {
-    if (param) {
-      return bal(add_min_binding(k, v, param[0]), param[1], param[2], param[3]);
-    } else {
-      return singleton(k, v);
-    }
-  };
-  var add_max_binding = function (k, v, param) {
-    if (param) {
-      return bal(param[0], param[1], param[2], add_max_binding(k, v, param[3]));
-    } else {
-      return singleton(k, v);
-    }
-  };
-  var join = function (l, v, d, r) {
-    if (l) {
-      if (r) {
-        var rh = r[4];
-        var lh = l[4];
-        if (lh > (rh + 2 | 0)) {
-          return bal(l[0], l[1], l[2], join(l[3], v, d, r));
-        } else if (rh > (lh + 2 | 0)) {
-          return bal(join(l, v, d, r[0]), r[1], r[2], r[3]);
-        } else {
-          return create(l, v, d, r);
-        }
-      } else {
-        return add_max_binding(v, d, l);
-      }
-    } else {
-      return add_min_binding(v, d, r);
-    }
-  };
-  var concat = function (t1, t2) {
-    if (t1) {
-      if (t2) {
-        var match = min_binding(t2);
-        return join(t1, match[0], match[1], remove_min_binding(t2));
-      } else {
-        return t1;
-      }
-    } else {
-      return t2;
-    }
-  };
-  var concat_or_join = function (t1, v, d, t2) {
-    if (d) {
-      return join(t1, v, d[0], t2);
-    } else {
-      return concat(t1, t2);
-    }
-  };
-  var split = function (x, param) {
-    if (param) {
-      var r = param[3];
-      var d = param[2];
-      var v = param[1];
-      var l = param[0];
-      var c = Caml_primitive.caml_string_compare(x, v);
-      if (c) {
-        if (c < 0) {
-          var match = split(x, l);
-          return /* tuple */[
-                  match[0],
-                  match[1],
-                  join(match[2], v, d, r)
-                ];
-        } else {
-          var match$1 = split(x, r);
-          return /* tuple */[
-                  join(l, v, d, match$1[0]),
-                  match$1[1],
-                  match$1[2]
-                ];
-        }
-      } else {
-        return /* tuple */[
-                l,
-                /* Some */[d],
-                r
-              ];
-      }
-    } else {
-      return /* tuple */[
-              /* Empty */0,
-              /* None */0,
-              /* Empty */0
-            ];
-    }
-  };
-  var merge = function (f, s1, s2) {
-    var exit = 0;
-    if (s1) {
-      var v1 = s1[1];
-      if (s1[4] >= height(s2)) {
-        var match = split(v1, s2);
-        return concat_or_join(merge(f, s1[0], match[0]), v1, Curry._3(f, v1, /* Some */[s1[2]], match[1]), merge(f, s1[3], match[2]));
-      } else {
-        exit = 1;
-      }
-    } else if (s2) {
-      exit = 1;
-    } else {
-      return /* Empty */0;
-    }
-    if (exit === 1) {
-      if (s2) {
-        var v2 = s2[1];
-        var match$1 = split(v2, s1);
-        return concat_or_join(merge(f, match$1[0], s2[0]), v2, Curry._3(f, v2, match$1[1], /* Some */[s2[2]]), merge(f, match$1[2], s2[3]));
-      } else {
-        throw [
-              Caml_builtin_exceptions.assert_failure,
-              [
-                "map.ml",
-                270,
-                10
-              ]
-            ];
-      }
-    }
-    
-  };
-  var filter = function (p, param) {
-    if (param) {
-      var d = param[2];
-      var v = param[1];
-      var l$prime = filter(p, param[0]);
-      var pvd = Curry._2(p, v, d);
-      var r$prime = filter(p, param[3]);
-      if (pvd) {
-        return join(l$prime, v, d, r$prime);
-      } else {
-        return concat(l$prime, r$prime);
-      }
-    } else {
-      return /* Empty */0;
-    }
-  };
-  var partition = function (p, param) {
-    if (param) {
-      var d = param[2];
-      var v = param[1];
-      var match = partition(p, param[0]);
-      var lf = match[1];
-      var lt = match[0];
-      var pvd = Curry._2(p, v, d);
-      var match$1 = partition(p, param[3]);
-      var rf = match$1[1];
-      var rt = match$1[0];
-      if (pvd) {
-        return /* tuple */[
-                join(lt, v, d, rt),
-                concat(lf, rf)
-              ];
-      } else {
-        return /* tuple */[
-                concat(lt, rt),
-                join(lf, v, d, rf)
-              ];
-      }
-    } else {
-      return /* tuple */[
-              /* Empty */0,
-              /* Empty */0
-            ];
-    }
-  };
-  var cardinal = function (param) {
-    if (param) {
-      return (cardinal(param[0]) + 1 | 0) + cardinal(param[3]) | 0;
-    } else {
-      return 0;
-    }
-  };
-  var bindings_aux = function (_accu, _param) {
-    while(true) {
-      var param = _param;
-      var accu = _accu;
-      if (param) {
-        _param = param[0];
-        _accu = /* :: */[
-          /* tuple */[
-            param[1],
-            param[2]
-          ],
-          bindings_aux(accu, param[3])
-        ];
-        continue ;
-        
-      } else {
-        return accu;
-      }
-    };
-  };
   var err = getAllResponseHeadersAsList(x);
   if (err.tag) {
     return err;
   } else {
     var insert = function (d, param) {
-      return add(param[0], param[1], d);
+      return Belt_MapString.set(d, param[0], param[1]);
     };
-    return /* Ok */Block.__(0, [List.fold_left(insert, /* Empty */0, err[0])]);
+    return /* Ok */Block.__(0, [Belt_List.reduce(err[0], Belt_MapString.empty, insert)]);
   }
 }
 
@@ -559,10 +82,10 @@ function overrideMimeType(mimetype, x) {
 
 function send(body, x) {
   if (typeof body === "number") {
-    if (body) {
-      return x.send(null);
-    } else {
+    if (body === 0) {
       return x.send();
+    } else {
+      return x.send(null);
     }
   } else {
     switch (body.tag | 0) {
@@ -571,10 +94,10 @@ function send(body, x) {
       case 1 : 
           return x.send(body[0]);
       case 2 : 
-          var form = List.fold_left((function (f, param) {
+          var form = Belt_List.reduce(body[0], new FormData(), (function (f, param) {
                   Web_formdata.append(param[0], param[1], f);
                   return f;
-                }), new FormData(), body[0]);
+                }));
           return x.send(form);
       case 3 : 
           return x.send(body[0]);
@@ -588,7 +111,8 @@ function setRequestHeader(header, value, x) {
 }
 
 function set_onreadystatechange(cb, x) {
-  return x.onreadystatechange = cb;
+  x.onreadystatechange = cb;
+  return /* () */0;
 }
 
 function get_onreadystatechange(x) {
@@ -598,7 +122,7 @@ function get_onreadystatechange(x) {
 function readyState(x) {
   var i = x.readystate;
   if (i > 4 || i < 0) {
-    var s = "Invalid return from 'readystate' of: " + i;
+    var s = "Invalid return from 'readystate' of: " + String(i);
     throw [
           Caml_builtin_exceptions.failure,
           s
@@ -612,21 +136,28 @@ function set_responseType(typ, x) {
   if (typeof typ === "number") {
     switch (typ) {
       case 0 : 
-          return x.responseType = "";
+          x.responseType = "";
+          return /* () */0;
       case 1 : 
-          return x.responseType = "arraybuffer";
+          x.responseType = "arraybuffer";
+          return /* () */0;
       case 2 : 
-          return x.responseType = "blob";
+          x.responseType = "blob";
+          return /* () */0;
       case 3 : 
-          return x.responseType = "document";
+          x.responseType = "document";
+          return /* () */0;
       case 4 : 
-          return x.responseType = "json";
+          x.responseType = "json";
+          return /* () */0;
       case 5 : 
-          return x.responseType = "text";
+          x.responseType = "text";
+          return /* () */0;
       
     }
   } else {
-    return x.responseType = typ[0];
+    x.responseType = typ[0];
+    return /* () */0;
   }
 }
 
@@ -702,7 +233,8 @@ function get_statusText(x) {
 }
 
 function set_timeout(t, x) {
-  return x.timeout = t;
+  x.timeout = t;
+  return /* () */0;
 }
 
 function get_timeout(x) {
@@ -710,7 +242,8 @@ function get_timeout(x) {
 }
 
 function set_withCredentials(b, x) {
-  return x.withCredentials = b;
+  x.withCredentials = b;
+  return /* () */0;
 }
 
 function get_withCredentials(x) {
@@ -718,7 +251,8 @@ function get_withCredentials(x) {
 }
 
 function set_onabort(cb, x) {
-  return x.onabort = cb;
+  x.onabort = cb;
+  return /* () */0;
 }
 
 function get_onabort(x) {
@@ -726,7 +260,8 @@ function get_onabort(x) {
 }
 
 function set_onerror(cb, x) {
-  return x.onerror = cb;
+  x.onerror = cb;
+  return /* () */0;
 }
 
 function get_onerror(x) {
@@ -734,7 +269,8 @@ function get_onerror(x) {
 }
 
 function set_onload(cb, x) {
-  return x.onload = cb;
+  x.onload = cb;
+  return /* () */0;
 }
 
 function get_onload(x) {
@@ -742,7 +278,8 @@ function get_onload(x) {
 }
 
 function set_onloadstart(cb, x) {
-  return x.onloadstart = cb;
+  x.onloadstart = cb;
+  return /* () */0;
 }
 
 function get_onloadstart(x) {
@@ -750,7 +287,8 @@ function get_onloadstart(x) {
 }
 
 function set_onprogress(cb, x) {
-  return x.onprogress = cb;
+  x.onprogress = cb;
+  return /* () */0;
 }
 
 function get_onprogress(x) {
@@ -758,7 +296,8 @@ function get_onprogress(x) {
 }
 
 function set_ontimeout(cb, x) {
-  return x.ontimeout = cb;
+  x.ontimeout = cb;
+  return /* () */0;
 }
 
 function get_ontimeout(x) {
@@ -766,7 +305,8 @@ function get_ontimeout(x) {
 }
 
 function set_onloadend(cb, x) {
-  return x.onloadend = cb;
+  x.onloadend = cb;
+  return /* () */0;
 }
 
 function get_onloadend(x) {
diff --git a/package.json b/package.json
index f9a355d..b0ddf1b 100644
--- a/package.json
+++ b/package.json
@@ -36,9 +36,9 @@
     "bs-platform": "^2.2.2"
   },
   "devDependencies": {
-    "browserify": "^14.0.0",
-    "bs-platform": "^2.2.2",
-    "npm-run-all": "4.0.2",
-    "watchify": "3.9.0"
+    "browserify": "^16.1.1",
+    "bs-platform": "^2.2.3",
+    "npm-run-all": "^4.1.2",
+    "watchify": "^3.11.0"
   }
 }
diff --git a/src/tea_app.ml b/src/tea_app.ml
index db50c65..9dd3ebb 100644
--- a/src/tea_app.ml
+++ b/src/tea_app.ml
@@ -110,7 +110,7 @@ let programStateWrapper initModel pump shutdown =
         | Some [] -> pending := None
         | Some msgs ->
           let () = pending := None in
-          List.iter handler (List.rev msgs)
+          Belt.List.forEach (Belt.List.reverse msgs) handler
       )
     | Some msgs -> pending := Some (msg :: msgs) in
   let finalizedCBs : 'msg Vdom.applicationCallbacks = {
@@ -194,7 +194,7 @@ let programLoop update view subscriptions initModel initCmd = function
     (* let () = Js.log (Vdom.createVNodeIntoElement callbacks !lastVdom parentNode) in *)
     (* We own the passed in node, clear it out TODO:  Clear it out properly *)
     (* let () = Js.log ("Blah", Web.Node.firstChild parentNode, Js.Null.test (Web.Node.firstChild parentNode), false, true) in *)
-    let clearPnode () = while (Js.Array.length (Web.Node.childNodes parentNode)) > 0 do
+    let clearPnode () = while (Belt.Array.length (Web.Node.childNodes parentNode)) > 0 do
         match Js.Null.toOption (Web.Node.firstChild parentNode) with
         | None -> ()
         | Some firstChild -> let _removedChild = Web.Node.removeChild parentNode firstChild in ()
diff --git a/src/tea_cmd.ml b/src/tea_cmd.ml
index fe93fb6..7cb0373 100644
--- a/src/tea_cmd.ml
+++ b/src/tea_cmd.ml
@@ -35,7 +35,7 @@ let rec run callbacks =
   function
   | NoCmd -> ()
   | Tagger tagger -> tagger callbacks
-  | Batch cmds -> List.fold_left (fun () cmd -> run callbacks cmd) () cmds
+  | Batch cmds -> Belt.List.reduceU cmds () (fun [@bs] () cmd -> run callbacks cmd)
   | EnqueueCall cb ->
     (* let () = Js.log ("Cmd.run", "enqueue", cb) in *)
     cb callbacks
diff --git a/src/tea_html.ml b/src/tea_html.ml
index 26bb402..3238c4d 100644
--- a/src/tea_html.ml
+++ b/src/tea_html.ml
@@ -224,8 +224,8 @@ let class' name = prop "className" name
 
 let classList classes =
   classes
-  |> List.filter (fun (_fst, snd) -> snd)
-  |> List.map (fun (fst, _snd) -> fst)
+  |. Belt.List.keep (fun (_fst, snd) -> snd)
+  |. Belt.List.map (fun (fst, _snd) -> fst)
   |> String.concat " "
   |> class'
 
diff --git a/src/tea_http.ml b/src/tea_http.ml
index d0b90e1..2c81416 100644
--- a/src/tea_http.ml
+++ b/src/tea_http.ml
@@ -12,7 +12,7 @@ type responseBody = Web.XMLHttpRequest.responseBody
 type response =
   { url : string
   ; status : response_status
-  ; headers : string Map.Make(String).t
+  ; headers : string Belt.Map.String.t
   ; body : responseBody
   }
 
@@ -93,7 +93,7 @@ let getString url =
 
 
 let send resultToMessage (Request (request, maybeEvents)) =
-  let module StringMap = Map.Make(String) in
+  let module StringMap = Belt.Map.String in
   let {method'; headers; url; body; expect; timeout; withCredentials } = request in
   let (Expect (typ, responseToResult)) = expect in
   Tea_cmd.call (fun callbacks ->
@@ -141,7 +141,7 @@ let send resultToMessage (Request (request, maybeEvents)) =
         with _ -> enqResError (BadUrl url) () in
       let () =
         let setHeader (Header (k, v)) = Web.XMLHttpRequest.setRequestHeader k v xhr in
-        let () = List.iter setHeader headers in
+        let () = Belt.List.forEach headers setHeader in
         let () = Web.XMLHttpRequest.set_responseType typ xhr in
         let () =
           match timeout with
diff --git a/src/tea_json.ml b/src/tea_json.ml
index f6ca0b8..6d8c2af 100644
--- a/src/tea_json.ml
+++ b/src/tea_json.ml
@@ -3,7 +3,7 @@ module Decoder = struct
 
   type error = String.t
 
-  module ObjectDict = Map.Make(String)
+  module ObjectDict = Belt.Map.String
 
   type ('input, 'result) t =
     Decoder of ('input -> ('result, error) Tea_result.t)
@@ -85,7 +85,7 @@ module Decoder = struct
                   | Tea_result.Ok r -> r
                   | Tea_result.Error e -> raise (ParseFail e)
                 ) in
-              try Tea_result.Ok (Array.to_list a |> List.map parse)
+              try Tea_result.Ok (Belt.List.fromArray a |. Belt.List.map parse)
               with ParseFail e -> Tea_result.Error ("list -> " ^ e)
             )
           | _ -> Tea_result.Error "Non-list value"
@@ -102,7 +102,7 @@ module Decoder = struct
                   | Tea_result.Ok r -> r
                   | Tea_result.Error e -> raise (ParseFail e)
                 ) in
-              try Tea_result.Ok (Array.map parse a)
+              try Tea_result.Ok (Belt.Array.map a parse)
               with ParseFail e -> Tea_result.Error ("array -> " ^ e)
             )
           | _ -> Tea_result.Error "Non-array value"
@@ -115,7 +115,7 @@ module Decoder = struct
           match classify value with
           | JSONObject o ->
             ( let keys = Js.Dict.keys o in
-              let parse k l =
+              let parse l k =
                 ( match Js.Dict.get o k with
                   | None -> raise (ParseFail ("Key is undefined: " ^ k))
                   | Some v ->
@@ -123,7 +123,7 @@ module Decoder = struct
                     | Tea_result.Ok r -> (k, r) :: l
                     | Tea_result.Error e -> raise (ParseFail e)
                 ) in
-              try Tea_result.Ok (Array.fold_right parse keys [])
+              try Tea_result.Ok (Belt.Array.reduceReverse keys [] parse)
               with ParseFail e -> Tea_result.Error ("Invalid keyValuePair parsing: " ^ e)
             )
           | _ -> Tea_result.Error "Non-keyValuePair value"
@@ -136,16 +136,16 @@ module Decoder = struct
           match classify value with
           | JSONObject o ->
             ( let keys = Js.Dict.keys o in
-              let parse k d =
+              let parse d k =
                 ( match Js.Dict.get o k with
                   | None -> raise (ParseFail ("Key is undefined: " ^ k))
                   | Some v ->
                     match decoder v with
-                    | Tea_result.Ok r -> ObjectDict.add k r d
+                    | Tea_result.Ok r -> ObjectDict.set d k r
                     | Tea_result.Error e -> raise (ParseFail e)
                 ) in
               let emptyDict = ObjectDict.empty in
-              try Tea_result.Ok (Array.fold_right parse keys emptyDict)
+              try Tea_result.Ok (Belt.Array.reduceReverse keys emptyDict parse)
               with ParseFail e -> Tea_result.Error ("Invalid dict parsing: " ^ e)
             )
           | _ -> Tea_result.Error "Non-dict value"
@@ -168,7 +168,7 @@ module Decoder = struct
       )
 
   let at fields dec =
-    List.fold_right field fields dec
+    Belt.List.reduceReverseU fields dec (fun [@bs] d k -> field k d)
 
   let index idx (Decoder decoder) =
     Decoder
@@ -176,9 +176,9 @@ module Decoder = struct
           let open Web.Json in
           match classify value with
           | JSONArray a ->
-            if idx < 0 || idx > (Array.length a)
+            if idx < 0 || idx > (Belt.Array.length a)
             then Tea_result.Error ("Array index out of range: " ^ (string_of_int idx))
-            else decoder a.(idx)
+            else decoder (Belt.Array.getUnsafe a idx)
           | _ -> Tea_result.Error "Non-array value"
       )
 
@@ -540,7 +540,7 @@ module Encoder = struct
     let aux o (k, v) =
       let () = Js.Dict.set o k v in
       o in
-    let o = List.fold_left aux (Js.Dict.empty ()) v in
+    let o = Belt.List.reduce v (Js.Dict.empty ()) aux in
     Json.of_type Json.Object o
 
   let array (v : 't array) = Json.of_type Json.Array v
diff --git a/src/tea_sub.ml b/src/tea_sub.ml
index 8d84ba7..0bdd4dc 100644
--- a/src/tea_sub.ml
+++ b/src/tea_sub.ml
@@ -38,7 +38,7 @@ let rec run : type msgOld msgNew . msgOld Vdom.applicationCallbacks ref -> msgNe
     let rec enable : type msg . msg Vdom.applicationCallbacks ref -> msg t -> unit = fun callbacks -> function
       | NoSub -> ()
       | Batch [] -> ()
-      | Batch subs -> List.iter (enable callbacks) subs
+      | Batch subs -> Belt.List.forEach subs (enable callbacks) 
       | Mapper (mapper, sub) ->
         let subCallbacks = mapper callbacks in
         enable subCallbacks sub
@@ -47,7 +47,7 @@ let rec run : type msgOld msgNew . msgOld Vdom.applicationCallbacks ref -> msgNe
     let rec disable : type msg . msg Vdom.applicationCallbacks ref -> msg t -> unit = fun callbacks -> function
       | NoSub -> ()
       | Batch [] -> ()
-      | Batch subs -> List.iter (disable callbacks) subs
+      | Batch subs -> Belt.List.forEach subs (disable callbacks)
       | Mapper (mapper, sub) ->
         let subCallbacks = mapper callbacks in
         disable subCallbacks sub
diff --git a/src/tea_task.ml b/src/tea_task.ml
index 24fd929..51ee539 100644
--- a/src/tea_task.ml
+++ b/src/tea_task.ml
@@ -141,7 +141,7 @@ let map6 func task1 task2 task3 task4 task5 task6 =
 let rec sequence = function
   | [] -> succeed []
   | task :: remainingTasks ->
-    map2 (fun l r -> l :: r (* TODO:  Replace with `List.cons` when updated to version 4.03 *)) task (sequence remainingTasks)
+    map2 (fun l r -> Belt.List.add r l) task (sequence remainingTasks)
 
 
 
diff --git a/src/vdom.ml b/src/vdom.ml
index 65289ff..aa861eb 100644
--- a/src/vdom.ml
+++ b/src/vdom.ml
@@ -115,16 +115,16 @@ let rec renderToHtmlString = function
       | Attribute (_namespace, k, v) -> String.concat "" [" "; k; "=\""; v; "\""]
       | Data (k, v) -> String.concat "" [" data-"; k; "=\""; v; "\""]
       | Event (_, _, _) -> ""
-      | Style s -> String.concat "" [" style=\""; String.concat ";" (List.map (fun (k, v) -> String.concat "" [k;":";v;";"]) s); "\""]
+      | Style s -> String.concat "" [" style=\""; String.concat ";" (Belt.List.mapU s (fun [@bs] (k, v) -> String.concat "" [k;":";v;";"])); "\""]
     in
     String.concat ""
       [ "<"
       ; namespace
       ; if namespace = "" then "" else ":"
       ; tagName
-      ; String.concat "" (List.map (fun p -> renderProp p) props)
+      ; String.concat "" (Belt.List.mapU props (fun [@bs] p -> renderProp p))
       ; ">"
-      ; String.concat "" (List.map (fun v -> renderToHtmlString v) vdoms)
+      ; String.concat "" (Belt.List.mapU vdoms (fun [@bs] v -> renderToHtmlString v))
       ; "</"
       ; tagName
       ; ">"
@@ -202,7 +202,7 @@ let patchVNodesOnElems_PropertiesApply_Add callbacks elem _idx = function
   | Attribute (namespace, k, v) -> Web.Node.setAttributeNsOptional elem namespace k v
   | Data (k, v) -> Js.log ("TODO:  Add Data Unhandled", k, v); failwith "TODO:  Add Data Unhandled"
   | Event (name, handlerType, cache) -> cache := eventHandler_Register callbacks elem name handlerType
-  | Style s -> List.fold_left (fun () (k, v) -> Web.Node.setStyleProperty elem k (Js.Null.return v)) () s
+  | Style s -> Belt.List.reduceU s () (fun [@bs] () (k, v) -> Web.Node.setStyleProperty elem k (Js.Null.return v))
 
 
 let patchVNodesOnElems_PropertiesApply_Remove _callbacks elem _idx = function
@@ -211,7 +211,7 @@ let patchVNodesOnElems_PropertiesApply_Remove _callbacks elem _idx = function
   | Attribute (namespace, k, _v) -> Web.Node.removeAttributeNsOptional elem namespace k
   | Data (k, v) -> Js.log ("TODO:  Remove Data Unhandled", k, v); failwith "TODO:  Remove Data Unhandled"
   | Event (name, _, cache) -> cache := eventHandler_Unregister elem name !cache
-  | Style s -> List.fold_left (fun () (k, _v) -> Web.Node.setStyleProperty elem k Js.Null.empty) () s
+  | Style s -> Belt.List.reduceU s () (fun [@bs] () (k, _v) -> Web.Node.setStyleProperty elem k Js.Null.empty)
 
 let patchVNodesOnElems_PropertiesApply_RemoveAdd callbacks elem idx oldProp newProp =
   let () = patchVNodesOnElems_PropertiesApply_Remove callbacks elem idx oldProp in
@@ -232,7 +232,7 @@ let patchVNodesOnElems_PropertiesApply_Mutate _callbacks elem _idx oldProp = fun
     (* let () = Js.log ("Mutating Style", elem, oldProp, _newProp) in *)
     match [@ocaml.warning "-4"] oldProp with
     | Style oldS ->
-      List.fold_left2 (fun () (ok, ov) (nk, nv) ->
+      Belt.List.reduce2U oldS s () (fun [@bs] () (ok, ov) (nk, nv) ->
           if ok = nk then
             if ov = nv then
               ()
@@ -241,7 +241,7 @@ let patchVNodesOnElems_PropertiesApply_Mutate _callbacks elem _idx oldProp = fun
           else
             let () = Web.Node.setStyleProperty elem ok Js.Null.empty in
             Web.Node.setStyleProperty elem nk (Js.Null.return nv)
-        ) () oldS s
+        )
     | _ -> failwith "Passed a non-Style to a new Style as a Mutations while the old Style is not actually a style!"
 
 let rec patchVNodesOnElems_PropertiesApply callbacks elem idx oldProperties newProperties =
@@ -309,12 +309,12 @@ let genEmptyProps length =
     | len -> aux (noProp :: lst) (len - 1)
   in aux [] length
 
-let mapEmptyProps props = List.map (fun _ -> noProp) props
+let mapEmptyProps props = Belt.List.mapU props (fun [@bs] _ -> noProp)
 
 
 let rec patchVNodesOnElems_ReplaceNode callbacks elem elems idx = function [@ocaml.warning "-4"]
   | (Node (newNamespace, newTagName, _newKey, _newUnique, newProperties, newChildren)) ->
-    let oldChild = elems.(idx) in
+    let oldChild = Belt.Array.getUnsafe elems idx in
     let newChild = Web.Document.createElementNsOptional newNamespace newTagName in
     let [@ocaml.warning "-8"] true = patchVNodesOnElems_Properties callbacks newChild (mapEmptyProps newProperties) newProperties in
     let childChildren = Web.Node.childNodes newChild in
@@ -348,11 +348,11 @@ and patchVNodesOnElems_MutateNode callbacks elem elems idx oldNode newNode =
      (Node (_newNamespace, newTagName, _newKey, newUnique, newProperties, newChildren) as newNode)) ->
     (* We are being ordered to mutate the node, the key's are already handled *)
     if oldUnique <> newUnique || oldTagName <> newTagName then
-      (* let () = Js.log ("Node test", "unique swap", elem, elems.(idx), newNode) in *)
+      (* let () = Js.log ("Node test", "unique swap", elem, Belt.Array.getUnsafe elems idx, newNode) in *)
       patchVNodesOnElems_ReplaceNode callbacks elem elems idx newNode
     else (* Same node type, just mutate things *)
-      (* let () = Js.log ("Node test", "non-unique mutate", elem, elems.(idx), newNode) in *)
-      let child = elems.(idx) in
+      (* let () = Js.log ("Node test", "non-unique mutate", elem, Belt.Array.getUnsafe elems idx, newNode) in *)
+      let child = Belt.Array.getUnsafe elems idx in
       let childChildren = Web.Node.childNodes child in
       let () = if patchVNodesOnElems_Properties callbacks child oldProperties newProperties then () else
           (* Properties mutation failed, full swap and log *)
@@ -378,13 +378,13 @@ and patchVNodesOnElems callbacks elem elems idx oldVNodes newVNodes =
     let _attachedChild = Web.Node.appendChild elem newChild in
     patchVNodesOnElems callbacks elem elems (idx + 1) [] newRest
   | _oldVnode :: oldRest, [] ->
-    let child = elems.(idx) in
+    let child = Belt.Array.getUnsafe elems idx in
     let _removedChild = Web.Node.removeChild elem child in
     patchVNodesOnElems callbacks elem elems idx oldRest [] (* Not changing idx so we can delete the rest too *)
   | CommentNode oldS :: oldRest, CommentNode newS :: newRest when oldS = newS -> patchVNodesOnElems callbacks elem elems (idx+1) oldRest newRest
   | Text oldText :: oldRest, Text newText :: newRest ->
     let () = if oldText = newText then () else
-      let child = elems.(idx) in
+      let child = Belt.Array.getUnsafe elems idx in
       Web.Node.set_nodeValue child newText in
     patchVNodesOnElems callbacks elem elems (idx+1) oldRest newRest
   | LazyGen (oldKey, _oldGen, oldCache) :: oldRest, LazyGen (newKey, newGen, newCache) :: newRest ->
@@ -396,30 +396,30 @@ and patchVNodesOnElems callbacks elem elems idx oldVNodes newVNodes =
       ( match oldRest, newRest with
         | LazyGen (olderKey, _olderGen, _olderCache) :: olderRest,
           LazyGen (newerKey, _newerGen, _newerCache) :: newerRest when olderKey = newKey && oldKey = newerKey ->
-          (* let () = Js.log ("Lazy older newer swap", olderKey, oldKey, newKey, newerKey, elem, elems.(idx)) in *)
+          (* let () = Js.log ("Lazy older newer swap", olderKey, oldKey, newKey, newerKey, elem, Belt.Array.getUnsafe elems idx) in *)
           (* TODO:  Test this branch, it is untested thus far *)
-          let firstChild = elems.(idx) in
-          let secondChild = elems.(idx+1) in
+          let firstChild = Belt.Array.getUnsafe elems idx in
+          let secondChild = Belt.Array.getUnsafe elems (idx+1) in
           let _removedChild = Web.Node.removeChild elem secondChild in
           let _attachedChild = Web.Node.insertBefore elem secondChild firstChild in
           patchVNodesOnElems callbacks elem elems (idx+2) olderRest newerRest
         | LazyGen (olderKey, _olderGen, olderCache) :: olderRest, _ when olderKey = newKey ->
-          (* let () = Js.log ("Lazy older match", olderKey, oldKey, newKey, elem, elems.(idx)) in *)
-          let oldChild = elems.(idx) in
+          (* let () = Js.log ("Lazy older match", olderKey, oldKey, newKey, elem, Belt.Array.getUnsafe elems idx) in *)
+          let oldChild = Belt.Array.getUnsafe elems idx in
           let _removedChild = Web.Node.removeChild elem oldChild in
           let oldVdom = !olderCache in
           let () = newCache := oldVdom in (* Don't forget to pass the cache along... *)
           patchVNodesOnElems callbacks elem elems (idx+1) olderRest newRest
         | _, LazyGen (newerKey, _newerGen, _newerCache) :: _newerRest when newerKey = oldKey ->
-          (* let () = Js.log ("Lazy newer match", "parse", oldKey, newKey, newerKey, elem, elems.(idx)) in *)
-          let oldChild = elems.(idx) in
+          (* let () = Js.log ("Lazy newer match", "parse", oldKey, newKey, newerKey, elem, Belt.Array.getUnsafe elems idx) in *)
+          let oldChild = Belt.Array.getUnsafe elems idx in
           let newVdom = newGen () in
           let () = newCache := newVdom in (* Don't forget to pass the cache along... *)
           let newChild = patchVNodesOnElems_CreateElement callbacks newVdom in
           let _attachedChild = Web.Node.insertBefore elem newChild oldChild in
           patchVNodesOnElems callbacks elem elems (idx+1) oldVNodes newRest
         | _ ->
-          (* let () = Js.log ("Lazy nomatch", oldKey, newKey, elem, elems.(idx)) in *)
+          (* let () = Js.log ("Lazy nomatch", oldKey, newKey, elem, Belt.Array.getUnsafe elems idx) in *)
           let oldVdom = !oldCache in
           let newVdom = newGen () in
           let () = newCache := newVdom in (* Don't forget to pass the cache along... *)
@@ -428,7 +428,7 @@ and patchVNodesOnElems callbacks elem elems idx oldVNodes newVNodes =
   | (Node (oldNamespace, oldTagName, oldKey, _oldUnique, _oldProperties, _oldChildren) as oldNode) :: oldRest,
     (Node (newNamespace, newTagName, newKey, _newUnique, _newProperties, _newChildren) as newNode) :: newRest ->
     if oldKey = newKey && oldKey <> "" then (* Do nothing, they are keyed identically *)
-      (* let () = Js.log ("Node test", "match", elem, elems.(idx), newNode) in *)
+      (* let () = Js.log ("Node test", "match", elem, Belt.Array.getUnsafe elems idx, newNode) in *)
       patchVNodesOnElems callbacks elem elems (idx+1) oldRest newRest
     else if oldKey = "" || newKey = "" then
       let () = patchVNodesOnElems_MutateNode callbacks elem elems idx oldNode newNode in
@@ -439,23 +439,23 @@ and patchVNodesOnElems callbacks elem elems idx oldVNodes newVNodes =
           Node (newerNamespace, newerTagName, newerKey, _newerUnique, _newerProperties, _newerChildren) :: newerRest
           when olderNamespace = newNamespace && olderTagName = newTagName && olderKey = newKey &&
                oldNamespace = newerNamespace && oldTagName = newerTagName && oldKey = newerKey ->
-          (* let () = Js.log ("Node test", "older newer swap", elem, elems.(idx), newNode) in *)
+          (* let () = Js.log ("Node test", "older newer swap", elem, Belt.Array.getUnsafe elems idx, newNode) in *)
           (* TODO:  Test this branch, it is untested thus far *)
-          let firstChild = elems.(idx) in
-          let secondChild = elems.(idx+1) in
+          let firstChild = Belt.Array.getUnsafe elems idx in
+          let secondChild = Belt.Array.getUnsafe elems (idx+1) in
           let _removedChild = Web.Node.removeChild elem secondChild in
           let _attachedChild = Web.Node.insertBefore elem secondChild firstChild in
           patchVNodesOnElems callbacks elem elems (idx+2) olderRest newerRest
         | Node (olderNamespace, olderTagName, olderKey, _olderUnique, _olderProperties, _olderChildren) :: olderRest, _
           when olderNamespace = newNamespace && olderTagName = newTagName && olderKey = newKey ->
-          (* let () = Js.log ("Node test", "older match", elem, elems.(idx), newNode) in *)
-          let oldChild = elems.(idx) in
+          (* let () = Js.log ("Node test", "older match", elem, Belt.Array.getUnsafe elems idx, newNode) in *)
+          let oldChild = Belt.Array.getUnsafe elems idx in
           let _removedChild = Web.Node.removeChild elem oldChild in
           patchVNodesOnElems callbacks elem elems (idx+1) olderRest newRest
         | _, Node (newerNamespace, newerTagName, newerKey, _newerUnique, _newerProperties, _newerChildren) :: _newerRest
           when oldNamespace = newerNamespace && oldTagName = newerTagName && oldKey = newerKey ->
-            (* let () = Js.log ("Node test", "newer match", elem, elems.(idx), newNode) in *)
-          let oldChild = elems.(idx) in
+            (* let () = Js.log ("Node test", "newer match", elem, Belt.Array.getUnsafe elems idx, newNode) in *)
+          let oldChild = Belt.Array.getUnsafe elems idx in
           let newChild = patchVNodesOnElems_CreateElement callbacks newNode in
           let _attachedChild = Web.Node.insertBefore elem newChild oldChild in
           patchVNodesOnElems callbacks elem elems (idx+1) oldVNodes newRest
@@ -464,7 +464,7 @@ and patchVNodesOnElems callbacks elem elems idx oldVNodes newVNodes =
           patchVNodesOnElems callbacks elem elems (idx+1) oldRest newRest
       )
   | _oldVnode :: oldRest, newNode :: newRest ->
-    let oldChild = elems.(idx) in
+    let oldChild = Belt.Array.getUnsafe elems idx in
     let newChild = patchVNodesOnElems_CreateElement callbacks newNode in
     let _attachedChild = Web.Node.insertBefore elem newChild oldChild in
     let _removedChild = Web.Node.removeChild elem oldChild in
diff --git a/src/web_xmlhttprequest.ml b/src/web_xmlhttprequest.ml
index 9ff6dc0..3d3f327 100644
--- a/src/web_xmlhttprequest.ml
+++ b/src/web_xmlhttprequest.ml
@@ -86,10 +86,10 @@ let getAllResponseHeadersAsList x =
   | Ok s -> Ok
     ( s
       |> Js.String.split "\r\n"
-      |> Array.map (Js.String.splitAtMost ": " ~limit:2)
-      |> Array.to_list
-      |> List.filter (fun a -> Array.length a == 2)
-      |> List.map
+      |. Belt.Array.map (Js.String.splitAtMost ": " ~limit:2)
+      |> Belt.List.fromArray
+      |. Belt.List.keep (fun a -> Belt.Array.length a == 2)
+      |. Belt.List.map
         ( function
           | [|key; value|] -> (key, value)
           | _ -> failwith "Cannot happen, already checked length"
@@ -97,12 +97,12 @@ let getAllResponseHeadersAsList x =
     )
 
 let getAllResponseHeadersAsDict x =
-  let module StringMap = Map.Make(String) in
+  let module StringMap = Belt.Map.String in
   match getAllResponseHeadersAsList x with
   | Tea_result.Error _ as err -> err
   | Tea_result.Ok l ->
-    let insert d (k, v) = StringMap.add k v d in
-    Tea_result.Ok (List.fold_left insert StringMap.empty l)
+    let insert d (k, v) = StringMap.set d k v in
+    Tea_result.Ok (Belt.List.reduce l StringMap.empty insert)
 
 let getResponseHeader key x = Js.Null.toOption (x##getResponse key)
 
@@ -119,10 +119,11 @@ let send body x =
   | FormDataBody f -> x##send__formdata f
   | FormListBody l ->
     let form =
-      List.fold_left
-        (fun f (key, value) -> let () = Web_formdata.append key value f in f)
+      Belt.List.reduce 
+        l
         (Web_formdata.create ())
-        l in
+        (fun f (key, value) -> let () = Web_formdata.append key value f in f)
+        in
     x##send__formdata form
   | DocumentBody d -> x##send__document d
   (* | BlobBody b -> x##send_blob b *)
diff --git a/test/test_client_attribute_removal.ml b/test/test_client_attribute_removal.ml
index 917fb2b..a23701a 100644
--- a/test/test_client_attribute_removal.ml
+++ b/test/test_client_attribute_removal.ml
@@ -39,7 +39,7 @@ let render_languages selected languages =
     | Some l -> language == l
     | None -> false
   in
-  let rendered = List.map (fun l -> lang l (is_selected selected l)) languages in
+  let rendered = Belt.List.mapU languages (fun [@bs] l -> lang l (is_selected selected l)) in
   ul [] rendered
 
 let update state = function