HigherOrderFunction tasks

.eslintrc.json

@@ -18,7 +18,7 @@
     ],
     "linebreak-style": [
       "error",
-      "unix"
+      "windows"
     ],
     "quotes": [
       "error",
@@ -265,4 +265,4 @@
       "never"
     ]
   }
-}
+}

Exercises/1-callback.js

@@ -1,5 +1,10 @@
 'use strict';
 
-const iterate = (obj, callback) => null;
+const iterate = (object, callback) => {
+  for (const key in object) {
+    const value = object[key];
+    callback(key, value, object);
+  }
+};
 
 module.exports = { iterate };

Exercises/2-closure.js

@@ -1,5 +1,6 @@
 'use strict';
 
-const store = x => null;
+const store = x => () => x;
+
 
 module.exports = { store };

Exercises/3-wrapper.js

@@ -1,5 +1,28 @@
 'use strict';
 
-const contract = (fn, ...types) => null;
+const contract = (fn, ...types) => (...args) => {
+  for (let i = 0; i < args.length; i++) {
+    const type = types[i].name;
+    const argType = typeof args[i];
+    if (type.toLowerCase() !== argType) {
+      throw new TypeError(
+        `Expected argument type "${type}"`
+      );
+    }
+  }
+
+  const res = fn(...args);
+  const resType = typeof res;
+  const lastType = types[types.length - 1].name;
+
+  if (resType !== lastType.toLowerCase()) {
+    throw new TypeError(
+      `Expected result type "${lastType}"`
+    );
+  }
+
+  return res;
+};
+
 
 module.exports = { contract };