Merge pull request #17 from praffn/array-filter

Add Array.prototype.filter implementation

Author: TheSTL

implementations/filter.js

@@ -0,0 +1,29 @@
+/**
+ *
+  filter() creates a new array with each element in the original
+  array if and only if the element pass the supplied predicate callback.
+
+  The predicate callback is invoked with three arguments:
+
+  - the value of the element
+  - the index of the element
+  - the Array object being traversed
+
+  The predicate callback is expected to return true if the element should
+  appear in the new array, otherwise false.
+
+  You can optionally specify a value to use as `this` in the callback
+  as the second argument to filter().
+
+  If no elements pass the predicate callback, an empty array will be returned
+*/
+
+Array.prototype.myFilter = function myFilter(callback, thisArg) {
+  const newArray = [];
+  for (let i = 0; i < this.length; i += 1) {
+    if (callback.call(thisArg, this[i], i, this)) {
+      newArray.push(this[i]);
+    }
+  }
+  return newArray;
+};