多种方式给JS对象添加属性和方法
方式一：定义对象时，直接添加属性和方法
function Person(name,age,sex){
this.name = name;
this.age = age;
this.sex = sex;
this.code = function(){
console.log(this.name + " is coding");
}
}
var xiaoming = new Person("xiaoming",10,"man");
console.log(xiaoming);// {name: "xiaoming", age: 10, sex: "man", code: ƒ}
xiaoming.code();// xiaoming is coding 运行结果：
Person {
name: 'xiaoming',
age: 10,
sex: 'man',
code: [Function (anonymous)]
}
Xiaoming is coding
方式二：通过"对象.属性名"添加属性和方法
function Fruit(){}
var tomato = new Fruit();
tomato.name = "xihongshi";
tomato.color = "red";
tomato.use = function(){
console.log(this.name + " can be to eat");
}
console.log(tomato);
tomato.use();
运行结果：
Fruit { name: 'xihongshi', color: 'red', use: [Function (anonymous)] }
Xihongshi can be to eat
方式三：通过"对象['属性名']"添加属性和方法
function Fruit(){}
var tomato = new Fruit();
tomato['name'] = "xihongshi";
tomato['color'] = "red";
tomato['use'] = function(){
console.log(this.name + " can be to eat");
}
console.log(tomato);
tomato.use();运行结果：
Fruit { name: 'xihongshi', color: 'red', use: [Function (anonymous)] }
Xihongshi can be to eat
方式四：通过 prototype (原型)添加属性和方法
function Animal(){};
Animal.prototype.foots = 4;
Animal.prototype.weight = 200;
Animal.prototype.hobby = "sing";
Animal.prototype.have = function(){
console.log("the animal have " + this.foots + " foot");
}
var pig = new Animal();
console.log(pig);
pig.have();// the animal have 4 foot
运行结果：
Animal {}
the animal have 4 foot
方式五：使用Object.assign添加属性和方法
function Person(name,age,sex){
this.name = name;
this.age = age;
this.sex = sex;
this.code = function(){
console.log(this.name + " is coding");
}
}
var xiaoming = new Person("xiaoming",10,"man");
console.log(xiaoming);// {name: "xiaoming", age: 10, sex: "man", code: ƒ}
xiaoming.code();// xiaoming is coding
var xiaoming2 = Object.assign({}, xiaoming, {test1:'demo1', test2:'demo2'}); // 第一个参数是 目标对象，后面的全是源对象，执行完之后返回目标对象
console.log(xiaoming2);// {name: "xiaoming", age: 10, sex: "man", code: ƒ, test1: 'demo1', test2: 'demo2'}
xiaoming2.code();// xiaoming is coding
运行结果：
Person {
name: 'xiaoming',
age: 10,
sex: 'man',
code: [Function (anonymous)]
}
xiaoming is coding
{
name: 'xiaoming',
age: 10,
sex: 'man',
code: [Function (anonymous)],
test1: 'demo1',
test2: 'demo2'
}
xiaoming is coding
方式六：使用扩展运算符...添加属性和方法
ES6新增语法，可以将两个对象合并成一个对象。将多个属性合并成1个对象。
function Person(name,age,sex){
this.name = name;
this.age = age;
this.sex = sex;
this.code = function(){
console.log(this.name + " is coding");
}
}
var xiaoming = new Person("xiaoming",10,"man");
console.log(xiaoming);// {name: "xiaoming", age: 10, sex: "man", code: ƒ}
xiaoming.code();// xiaoming is coding
var xiaoming2 = {...xiaoming, test1:'demo1', test2:'demo2'};
console.log(xiaoming2);// {name: "xiaoming", age: 10, sex: "man", code: ƒ, test1: 'demo1', test2: 'demo2'}
xiaoming2.code();// xiaoming is coding
运行结果：
Person {
name: 'xiaoming',
age: 10,
sex: 'man',
code: [Function (anonymous)]
}
xiaoming is coding
{
name: 'xiaoming',
age: 10,
sex: 'man',
code: [Function (anonymous)],
test1: 'demo1',
test2: 'demo2'
}
xiaoming is coding