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JavaScript高级程序设计读书笔记
这本书继承的实现列举了好几种,里面有两种是比较靠谱的。
1 组合继承
//父构造函数 function Super(name) { this.name = name; this.colors = [‘black‘, ‘red‘]; }
Super.prototype.getName = function() { return this.name; }
//子构造函数 function Sub(name, age) { Super.call(this, name); this.age = age; }
//把Sub的原型修改为Super的实例,就能继承Super.prototype中的属性和方法了,
//这样存在的问题是:把name和colors属性也添加到Sub.prototype中了,这部分对实例是不可见的,
//因为调用new Sub()生成实例时,会把name和colors添加为实例属性 Sub.prototype = new Super(); Sub.prototype.getAge = function(){ return this.age; }
//前面修改Sub.prototype时,导致Sub.prototype.constructor指向了Super,所以要修改回来
Sub.prototype.constructor = Sub;
var ins1 = new Sub(‘mengxb‘, 28);
2 寄生组合式继承
function Object(o) { function F() {}; F.prototype = o; return new F(); } function inheritPrototype(sub, super) { var prototype = Object(super.prototype); sub.prototype = prototype; sub.prototype.construtor = sub; } function Super(name) { this.name = name; this.colors = [‘black‘, ‘red‘]; } Super.prototype.getName = function() { return this.name; } function Sub(name, age) { Super.call(this, name); this.age = age; } inheritPrototype(Sub, Super); Sub.prototype.getAge = function(){ return this.age; }
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原文地址:http://www.cnblogs.com/mengxiang-1234/p/4685972.html