Created
July 12, 2011 18:15
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Prebound JS methods
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <script type="application/javascript;version=1.7"> | |
| /** | |
| * Proxy handler to automatically bind methods. | |
| */ | |
| function prebound(obj) { | |
| return { | |
| memoized: {}, | |
| get: function get(receiver, name) { | |
| var func = obj[name]; | |
| if (!func || typeof func != "function") { | |
| return func; | |
| } | |
| return this.memoized[name] || (this.memoized[name] = func.bind(receiver)); | |
| }, | |
| delete: function delete_(receiver, name) { | |
| delete obj[name]; | |
| delete this.memoized[name]; | |
| }, | |
| set: function set(receiver, name, value) { | |
| obj[name] = value; | |
| delete this.memoized[name]; | |
| } | |
| } | |
| } | |
| /** | |
| * Wraps a constructor function and injects a proxy that prebinds methods. | |
| */ | |
| function withPreboundMethods(ctor) { | |
| var callTrap = function(args) {} | |
| var constructTrap = function(args) { | |
| return Proxy.create(prebound(new ctor(args)), Object.prototype); | |
| }; | |
| return Proxy.createFunction(ctor, callTrap, constructTrap); | |
| } | |
| /** | |
| * Example | |
| */ | |
| function Foobar() {} | |
| Foobar.prototype = { | |
| method: function method() { | |
| console.log("Are we this yet?", this == f); | |
| } | |
| }; | |
| Foobar = withPreboundMethods(Foobar); | |
| var f = new Foobar(); | |
| var meth = f.method; | |
| meth(); | |
| </script> | |
| </head> | |
| <body> | |
| </body> | |
| </html> |
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