一个javascript沿袭的基础类Base.js

一个javascript继承的基础类Base.js

一个javascript继承的基础类Base.js

官网:http://dean.edwards.name

http://dean.edwards.name/weblog/2006/03/base/

一个javascript继承的基础类
首先我是一个面向对象的程序员,并且javascript支持prototype 方式继承,例如:

function Animal(name) {};Animal.prototype.eat = function() {};Animal.prototype.say = function(message) {};

1.我想不用prototype并容易地创建类.
2.我想用一个方法重写父类方法,就像java支持的那样.
3.在原型阶段我想要避免调用一个类的构造函数函数.
4.我想在类上容易的创建静态方法或属性.
5.我想实现上述功能不用全局函数
6.我想实现上诉功能不影响Object.prototype

/*    Base.js, version 1.1a    Copyright 2006-2010, Dean Edwards    License: http://www.opensource.org/licenses/mit-license.php*/var Base = function() {    // dummy};Base.extend = function(_instance, _static) { // subclass    var extend = Base.prototype.extend;        // build the prototype    Base._prototyping = true;    var proto = new this;    extend.call(proto, _instance);  proto.base = function() {    // call this method from any other method to invoke that method's ancestor  };    delete Base._prototyping;        // create the wrapper for the constructor function    //var constructor = proto.constructor.valueOf(); //-dean    var constructor = proto.constructor;    var klass = proto.constructor = function() {        if (!Base._prototyping) {            if (this._constructing || this.constructor == klass) { // instantiation                this._constructing = true;                constructor.apply(this, arguments);                delete this._constructing;            } else if (arguments[0] != null) { // casting                return (arguments[0].extend || extend).call(arguments[0], proto);            }        }    };        // build the class interface    klass.ancestor = this;    klass.extend = this.extend;    klass.forEach = this.forEach;    klass.implement = this.implement;    klass.prototype = proto;    klass.toString = this.toString;    klass.valueOf = function(type) {        //return (type == "object") ? klass : constructor; //-dean        return (type == "object") ? klass : constructor.valueOf();    };    extend.call(klass, _static);    // class initialisation    if (typeof klass.init == "function") klass.init();    return klass;};Base.prototype = {        extend: function(source, value) {        if (arguments.length > 1) { // extending with a name/value pair            var ancestor = this[source];            if (ancestor && (typeof value == "function") && // overriding a method?                // the valueOf() comparison is to avoid circular references                (!ancestor.valueOf || ancestor.valueOf() != value.valueOf()) &&                /\bbase\b/.test(value)) {                // get the underlying method                var method = value.valueOf();                // override                value = function() {                    var previous = this.base || Base.prototype.base;                    this.base = ancestor;                    var returnValue = method.apply(this, arguments);                    this.base = previous;                    return returnValue;                };                // point to the underlying method                value.valueOf = function(type) {                    return (type == "object") ? value : method;                };                value.toString = Base.toString;            }            this[source] = value;        } else if (source) { // extending with an object literal            var extend = Base.prototype.extend;            // if this object has a customised extend method then use it            if (!Base._prototyping && typeof this != "function") {                extend = this.extend || extend;            }            var proto = {toSource: null};            // do the "toString" and other methods manually            var hidden = ["constructor", "toString", "valueOf"];            // if we are prototyping then include the constructor            var i = Base._prototyping ? 0 : 1;            while (key = hidden[i++]) {                if (source[key] != proto[key]) {                    extend.call(this, key, source[key]);                }            }            // copy each of the source object's properties to this object            for (var key in source) {                if (!proto[key]) extend.call(this, key, source[key]);            }        }        return this;    }};// initialiseBase = Base.extend({    constructor: function() {        this.extend(arguments[0]);    }}, {    ancestor: Object,    version: "1.1",        forEach: function(object, block, context) {        for (var key in object) {            if (this.prototype[key] === undefined) {                block.call(context, object[key], key, object);            }        }    },            implement: function() {        for (var i = 0; i < arguments.length; i++) {            if (typeof arguments[i] == "function") {                // if it's a function, call it                arguments[i](this.prototype);            } else {                // add the interface using the extend method                this.prototype.extend(arguments[i]);            }        }        return this;    },        toString: function() {        return String(this.valueOf());    }});

?extend

var object = new Base;object.extend({    value: "some data",    method: function() {        alert("Hello World!");    }});object.method();// ==> Hello World!

?base

var object = new Base;object.method = function() {    alert("Hello World!");};object.extend({    method: function() {        // call the "super" method        this.base();        // add some code        alert("Hello again!");    }});object.method();// ==> Hello World!// ==> Hello again!

?Creating Classes

var Animal = Base.extend({    constructor: function(name) {        this.name = name;    },        name: "",        eat: function() {        this.say("Yum!");    },        say: function(message) {        alert(this.name + ": " + message);    }});var Cat = Animal.extend({    eat: function(food) {        if (food instanceof Mouse) this.base();        else this.say("Yuk! I only eat mice.");    }});    var Mouse = Animal.extend();