Another update from ingydotnet^djgoku

Task/Associative-array-Creation/JavaScript/associative-array-creation-1.js

@@ -1,13 +1,21 @@
 var assoc = {};
+
 assoc['foo'] = 'bar';
 assoc['another-key'] = 3;
-assoc.thirdKey = 'we can also do this!'; // dot notation can be used if the property name
-                                         // is a valid identifier
-assoc[2] = 'the index here is the string "2"';
-assoc[null] = 'this also works';
-assoc[(function(){return 'expr';})()] = 'Can use expressions too';
 
+// dot notation can be used if the property name is a valid identifier
+assoc.thirdKey = 'we can also do this!';
+assoc[2] = "the index here is the string '2'";
+
+//using JavaScript's object literal notation
+var assoc = {
+  foo: 'bar',
+  'another-key': 3 //the key can either be enclosed by quotes or not
+};
+
+//iterating keys
 for (var key in assoc) {
+  // hasOwnProperty() method ensures the property isn't inherited
   if (assoc.hasOwnProperty(key)) {
     alert('key:"' + key + '", value:"' + assoc[key] + '"');
   }

Task/Associative-array-Creation/JavaScript/associative-array-creation-2.js

@@ -1,4 +1,22 @@
-var assoc = {
-  foo: 'bar',
-  'another-key': 3 //the key can either be enclosed by quotes or not
-};
+var map = new Map(),
+    fn = function () {},
+    obj = {};
+
+map.set(fn, 123);
+map.set(obj, 'abc');
+map.set('key', 'val');
+map.set(3, x => x + x);
+
+map.get(fn); //=> 123
+map.get(function () {}); //=> undefined because not the same function
+map.get(obj); //=> 'abc'
+map.get({}); //=> undefined because not the same object
+map.get('key'); //=> 'val'
+map.get(3); //=> (x => x + x)
+
+map.size; //=> 4
+
+//iterating using ES6 for..of syntax
+for (var key of map.keys()) {
+  console.log(key + ' => ' + map.get(key));
+}