[英]Simple JavaScript Inheritence plugin error
我阅读了John Resig在一个简单JavaScript继承插件上的博客文章,他基于base2和原型编写了该插件。
示例代码在这里: http : //jsfiddle.net/rFfX9/
//'use strict';
/* Simple JavaScript Inheritance
* By John Resig http://ejohn.org/
* MIT Licensed.
*/
// Inspired by base2 and Prototype
(function () {
var initializing = false, fnTest = /xyz/.test(function () { xyz; }) ? /\b_super\b/ : /.*/;
// The base Class implementation (does nothing)
this.Class = function () { };
// Create a new Class that inherits from this class
Class.extend = function (prop) {
var _super = this.prototype;
// Instantiate a base class (but only create the instance,
// don't run the init constructor)
initializing = true;
var prototype = new this();
initializing = false;
// Copy the properties over onto the new prototype
for (var name in prop) {
// Check if we're overwriting an existing function
prototype[name] = typeof prop[name] == "function" &&
typeof _super[name] == "function" && fnTest.test(prop[name]) ?
(function (name, fn) {
return function () {
var tmp = this._super;
// Add a new ._super() method that is the same method
// but on the super-class
this._super = _super[name];
// The method only need to be bound temporarily, so we
// remove it when we're done executing
var ret = fn.apply(this, arguments);
this._super = tmp;
return ret;
};
})(name, prop[name]) :
prop[name];
}
// The dummy class constructor
function Class() {
// All construction is actually done in the init method
if (!initializing && this.init)
this.init.apply(this, arguments);
}
// Populate our constructed prototype object
Class.prototype = prototype;
// Enforce the constructor to be what we expect
Class.prototype.constructor = Class;
// And make this class extendable
Class.extend = arguments.callee;
return Class;
};
})();
这可行。 但是,当我取消评论'use strict';
在顶部,它引发异常,但无法找出解决方案。 有任何想法吗?
在这种情况下,当您调用匿名函数时, this
将是undefined
您不会将函数作为对象的方法来调用。 在非严格模式下, this
将是window
对象。
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