// 1.对象字面量或者对象直接量
var obj = {
name:'张三',
sex:'male'
}
obj.name='李四'
// 2.构造函数，构造函数写出来之后可以通过new关键字去实例化一个对象
// 2.1用系统内自带的构造函数
var obj = new Object() //跟对象字面量相等
obj.name='张三'
obj.sex='男的'
console.log(obj);
对象和构造函数是两码事，对象是通过实例化构造函数new出的对象实例。对象是通过实例化构造函数而创建的一个对象实例。
// 3.1自定义构造函数（模块化、插件、组件化）
function Person() {
this.name = "张三";
this.sex = '男';
this.walk = function () {
console.log('am walking');
}
}
// new 之后才会用this
var girl1 = new Person()
var girl2 = new Person()
console.log(girl1);//Person {name: "张三", sex: "男", walk: ƒ}
console.log(girl2);//Person {name: "张三", sex: "男", walk: ƒ}
girl1.name = 'marry'
// 通过构造函数构造出来的对象相互之间不影响，完全是两个对象
// 通过这种方法去写程序复用性就高了，每一次都是new出不同的对象
console.log(girl1); //Person {name: "marry", sex: "男", walk: ƒ}
console.log(girl2); //Person {name: "张三", sex: "男", walk: ƒ}
0// 3.自定义构造函数（模块化、插件、组件化）
function Person() {
this.name = "张三";
this.sex = '男';
this.weight = 120
this.walk = function () {
this.weight--
console.log(this.weight);
}
this.eat = function () {
this.weight--
console.log(this.weight);
}
}
var girl1 = new Person()
var girl2 = new Person()
girl1.walk()//119
girl1.walk()//118
console.log(girl2.weight);//120
//3.2构造函数的参数
function Person(name, sex, weight) {
this.name = name;
this.sex = sex;
this.weight = weight
this.walk = function () {
this.weight--
console.log(this.weight);
}
this.eat = function () {
this.weight--
console.log(this.weight);
}
}
// 创造了两个完全不同的女孩，她们之间是完全不影响的
var girl1 = new Person('ww', '女', 145)
var girl2 = new Person('aa', '女', 146)
console.log(girl1);//Person {name: "ww", sex: "女", weight: 145, walk: ƒ, eat: ƒ}
console.log(girl2);//Person {name: "aa", sex: "女", weight: 146, walk: ƒ, eat: ƒ}
以对象形式传参，更好维护
//3.2 以对象形式传参，更好维护
function Person(opt) {
this.name = opt.name;
this.sex = opt.sex;
this.weight = opt.weight
this.walk = function () {
this.weight--
console.log(this.weight);
}
this.eat = function () {
this.weight--
console.log(this.weight);
}
}
// 创造了两个完全不同的女孩，她们之间是完全不影响的
//参数以属性名排，开发的时候这么做
var girl1 = new Person({
name: 'qq', sex: '女', weight: '123'
})
var girl2 = new Person({
name: 'uu', sex: '女', weight: '124'
})
console.log(girl1);//Person {name: "qq", sex: "女", weight: "123", walk: ƒ, eat: ƒ}
console.log(girl2);//Person {name: "uu", sex: "女", weight: "124", walk: ƒ, eat: ƒ}
//4.1 this 没有实例化的时候指向window，实例化之后指向 实例化的那个对象
function Car() {
this.color = 'red'
}
Car()//this 指向window·
//new 是为了改变this指向
var car = new Car() //this 指向car
// 4.2 构造函数原理,构造函数实例化仅仅是系统内部给了我一个 new，
//new 的作用就是把 this 造出来以后指向实例化，this 是隐式的
//new 就是把原本指向 window 的this 转向 实例化对象
// 4.2.1
function Car(color, brand) {
// this.color = 'red'
var me = {}
me.color = color
me.brand = brand
return me
}
var car = Car('red', 'byd')
console.log(car);//{color: "red", brand: "byd"}
// 4.2.2
function Cars(laojia, nling) {
// this.color = 'red'
this.laojia = laojia
this.nling = nling
return this
}
var car = Car('jx', '22')
console.log(car);//{color: "jx", brand: "22"}
// 4.2.3
function Carss(xuexiao, address) {
this.xuexiao = xuexiao
this.xuexiao = xuexiao
}
var car = new Car('shizhuan', 'ganzho')
console.log(car);//{color: "shizhuan", brand: "ganzho"}