WCEU79Eb

1Static variables with John Resig's simple class pattern?
2function makeClass() {
3    return function _class() {
4        if(this instanceof _class) {
5            if(typeof this.init === 'function') {
6                this.init.apply(this, arguments);
7            }
8        } else {
9            throw new Error('Constructor called as a function');
10        }
11    };
12}
13	
14var MyClass = makeClass();
15
16MyClass.prototype = {
17    init: function(width, height) { ... },
18    clear: function(ctx) {... },
19    draw: function(ctx) { ... }
20}
21	
22MyClass.myVariable = 42;
23	
24MyClass.prototype.xxx: 3, // ...
25var t1 = new MyClass();
26console.log(t1.xxx); // 3
27	
28var t2 = new MyClass();
29t2.xxx = 5;
30console.log(t1.xxx); // still 3 :(
31	
32MyClass.xxx = 3;
33	
34init: function() {
35      var xxx = 3;
36      MyClass.prototype.getXXX = function() {
37         return xxx;
38      };
39      MyClass.prototype.setXXX = function(newXXX) {
40         xxx = newXXX;
41      }
42   }
43	
44var t1 = new MyClass();
45  var t2 = new MyClass();
46  console.log(t1.getXXX()); // 3
47  console.log(t2.getXXX()); // 3
48  t1.setXXX(5);
49  console.log(t1.getXXX()); // 5 now
50  console.log(t2.getXXX()); // 5 as well, behold the power of closures!
51	
52var statics = (function() {
53    var map = new WeakMap;
54    return function(inst) {
55        var ctor = inst.constructor;
56        return map.get(ctor) || map.set(ctor, {});
57    };
58})();
59	
60var a = function() {};
61var b = function() {};
62
63var inst1 = new a;
64var inst2 = new a;
65var inst3 = new b;
66
67statics(inst1).foo = 123;
68statics(inst3).foo = 456;
69
70console.log( statics(inst1).foo );  // 123
71console.log( statics(inst2).foo );  // 123
72console.log( statics(inst3).foo );  // 456