Mixins in JavaScript
This post has been updated at 09/07/2011.
Thanks to JavaScript flexibility it's incredibly easy to use mixins:
Thanks to JavaScript flexibility it's incredibly easy to use mixins:
var sys = require("sys");
var extend = function extend (another) {
var prototype = this.__proto__;
this.__proto__ = another;
another.__proto__ = prototype;
return this;
};
Object.defineProperty(Object.prototype, "extend", {value: extend });
var Model = new Function();
var SQLFindersMixin = {
findBySQL: function (query) {
sys.puts("Finding by SQL: " + query);
}
};
Model.prototype.extend(SQLFindersMixin);
var instance = new Model();
instance.findBySQL("SELECT * from POSTS");
So how does it work? Well we simply inject another item into the prototype chain, so instead of Model.prototype -> Object.prototype we turn it into Model.prototype -> SQLFindersMixin -> Object.prototype. Easy and useful.