extend (继承)

如何用 es5 实现继承

Father.prototype = {    eat:function(){        console.log(this.name+' eat something.')    }}function Father(name) {    this.name = name    this.attr = "father's attr."}function Super() {    this.constructor = Child}Super.prototype = Father.prototypeChild.prototype = new Super() // 继承父类的原型方法function Child() {    Father.apply(this, arguments) // 继承父类的属性    this.attr = "child's attr"}复制代码

测试

var child = new Child('Foo')console.log(child,child.attr)console.log(child instanceof Child, child instanceof Father)child.eat()console.log(child.newAttr)Father.prototype.newAttr = '123'console.log(child.newAttr)console.log(Child.prototype.constructor === Child)复制代码

结果

Child { name: 'Foo', attr: 'child\'s attr' } 'child\'s attr'true trueFoo eat something.undefined123true复制代码