// 继承方式2 ==> 置换后的原型继承
function Person() {} Person.prototype = { say: function() {} } var xiaohong = new Person();// 继承方式3 ==> 寄生式继承
var obj = { val: 100 }; var newObj = Object.create( obj );// 继承方式4 ==> 混入继承
function extend( o1, o2 ) { for( var key in o2 ) { o1[key] = o2[key]; } } var o = { abc: 888 }; var o2 = { aaa: 111, bbb: 222, ccc: 333 }; extend( o, o2 );// 继承方式5 ==> 对象冒充( 构造函数借用 )
function Person( name, age, sex ) { this.name = name; this.age = age; this.sex = sex; }function Student( name, age, sex ) {
this.Person = Person; this.Person( name, age, sex ); delete this.Person; }function Student( name, age, sex ) {
//Person.call( this, name, age, sex ); Person.apply( this, arguments ); }var xiaohong = new Student('小红', 16);
console.log( xiaohong );// 继承方式6 ==> 原型组合继承
function Person( name, age, sex ) { this.name = name; this.age = age; this.sex = sex; }Person.prototype = {
run: function() { console.log('人都会跑'); } };function Student( name, age, sex ) {
Person.apply( this, arguments ); }// 解决方案1：
// 这样可以，但是不建议，因为一定会给Student添加一些额外的方法， // 这些方法不应该和Person共享 //Student.prototype = Person.prototype;// 解决方案2，混入继承，可取，用的也比较多
//extend( Student.prototype, Person.prototype );// 解决方案3，原型寄生组合式继承
//Student.prototype = Object.create( Person.prototype );// 解决方案4，
Student.prototype = new Person;// xiaofang ==> Student.prototype ==> Person.prototype ==> Object.prototype ==> null
var xiaofang = new Student( '小芳', 17, '女' ); xiaofang.run(); /* * 理想的继承解决方案： * */ function Person( name, age, sex ) { this.name = name; this.age = age; this.sex = sex; }Person.prototype = {
run: function() { console.log('人都会跑'); } };function Student( name, age, sex ) {
Person.apply( this, arguments ); }// 让学生实例，继承Student.prototype & Person.prototype
Student.prototype = Object.create( Person.prototype );// 再给Student扩展自己独有的方法
extend( Student.prototype, {} );