一： 原型链
Grand.prototype.lastName = "Niclo";
function Grand() {
}
var grand = new Grand();
Father.prototype = grand;
function Father() {
this.name = 'hello'
}
var father = new Father();
Son.prototype = father
function Son() {
}
var son = new Son()
比如son只想继承lastName,但是Father里面的name也继承了，继承了很多没用的属性
缺点：
- 过多的继承了没用的属性
二：借用构造函数
Person.prototype.sayHello = function() {
console.log('say hello')
}
function Person(name,age,sex) {
this.name = name;
this.age = age;
this.sex = sex;
}
function Student(name,age,sex,grade) {
Person.call(this,name,age,sex);
this.grade = grade;
}
var student = new Student();
缺点：
- 不能继承借用构造函数的原型
- 每次构造函数都要多走一个函数
三： 共享原型
Father.prototype.lastName="shi";
function Father() {
}
var father = new Father();
Son.prototype = Father.prototype;
function Son() {
}
var son = new Son()
//把上面内容封装成函数
Father.prototype.lastName="shi";
function Father() {
}
function Son() {
}
function inherit(Target,Origin) {
Target.prototype = Origin.prototype
}
inherit(Son,Father)
var son = new Son()
var father = new Father()
Son.prototype.sex = 'male'
son.sex //male
father.sex //male
发现Son原型里自定义sex后,影响father了
缺点：
- 不能随便改动自己的属性
四： 圣杯模式
Father.prototype.lastName="shi";
function Father() {
}
function Son() {
}
function inherit(Target,Origin) {
function F() {
}
F.prototype = Origin.prototype
Target.prototype = new F()
}
inherit(Son,Father)
var son = new Son()
var father = new Father()
Son.prototype.sex = 'male'
son.sex //male
father.sex //undefined
