75 lines
2.1 KiB
JavaScript
75 lines
2.1 KiB
JavaScript
/* based on Simple JavaScript Inheritance
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* By John Resig http://ejohn.org/
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* MIT Licensed.
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*/
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var initializing = false, fnTest = /xyz/.test(function(){xyz;}) ? /\b_super\b/ : /.*/;
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// The base Class implementation (does nothing)
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var Class = function(){};
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// Create a new Class that inherits from this class
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Class.extend = function() {
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var args = Array.prototype.slice.call(arguments);
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var name = 'Class';
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var parent = this;
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var prop = {};
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if(typeof args[0] == 'string') name = args.shift();
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if(args.length >= 2) parent = args.shift();
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prop = args.shift();
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// Copy prototype from the parent object
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var prototype = {};
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for(var name in parent.prototype) {
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prototype[name] = parent.prototype[name];
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}
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// Copy the properties over onto the new prototype
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for(var name in prop) {
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if(typeof prop[name] == "function" && fnTest.test(prop[name])) {
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// this is a function that references _super, so we have to wrap it
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// and provide it with its super function
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prototype[name] = (function(name, fn){
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return function() {
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var tmp = this._super;
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// Add a new ._super() method that is the same method
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// but on the super-class
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if(typeof parent.prototype[name] == 'undefined') {
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if(name == 'init') this._super = parent.prototype.constructor;
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else this._super = function() { throw new Error('Called _super in method without a parent'); }
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} else this._super = parent.prototype[name];
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// The method only need to be bound temporarily, so we
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// remove it when we're done executing
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var ret = fn.apply(this, arguments);
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this._super = tmp;
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return ret;
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};
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})(name, prop[name]);
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} else {
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prototype[name] = prop[name];
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}
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}
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// The dummy class constructor
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function Class() {
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// All construction is actually done in the init method
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if(this.init) this.init.apply(this, arguments);
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}
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// Populate our constructed prototype object
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Class.prototype = prototype;
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// Enforce the constructor to be what we expect
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Class.prototype.constructor = Class;
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// And make this class extendable
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Class.extend = arguments.callee;
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return Class;
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};
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module.exports = Class;
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