Add polyfills for old IEs.

Author: Eric Wendelin

polyfills.js

@@ -0,0 +1,48 @@
+// ES5 Polyfills
+// See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map
+if (!Array.prototype.map) {
+    Array.prototype.map = function(callback, thisArg) {
+        var O = Object(this);
+        var len = O.length >>> 0;
+        var T;
+        if (arguments.length > 1) {
+            T = thisArg;
+        }
+
+        var A = new Array(len);
+        var k = 0;
+
+        while (k < len) {
+            var kValue, mappedValue;
+            if (k in O) {
+                kValue = O[k];
+                mappedValue = callback.call(T, kValue, k, O);
+                A[k] = mappedValue;
+            }
+            k++;
+        }
+
+        return A;
+    };
+}
+
+// See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter
+if (!Array.prototype.filter) {
+    Array.prototype.filter = function(callback/*, thisArg*/) {
+        var t = Object(this);
+        var len = t.length >>> 0;
+
+        var res = [];
+        var thisArg = arguments.length >= 2 ? arguments[1] : void 0;
+        for (var i = 0; i < len; i++) {
+            if (i in t) {
+                var val = t[i];
+                if (callback.call(thisArg, val, i, t)) {
+                    res.push(val);
+                }
+            }
+        }
+
+        return res;
+    };
+}