构造对象的2中方式

1. 构造函数+prototype

let peopleList = []
const ageList = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]

function createPeople(age) {
  const object = Object.create(createPeople.peoplePrototype)
  object.age = age
  return object
}
createPeople.peoplePrototype = {
  //将原型放在函数上
  getDoubleAge() {
    return this.age * 2
  },
  constructor: createPeople, // 方便使用原型找到构造函数
}

for (let i = 0; i <= 11; i++) {
  peopleList[i] = createPeople(ageList[i])
}

使用 new 操作符优化

let peopleList = []
const ageList = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]

function People(age) {
  this.age = age
}
People.prototype.getDoubleAge = function () {
  return this.age * 2
}

for (let i = 0; i <= 11; i++) {
  peopleList[i] = new People(ageList[i])
}

new 自动做了四件事

1. 自动创建空对象
2. 自动为空对象关联原型，原型地址指定为 X.prototype
3. 自动将空对象作为 this 关键字运行构造函数
4. 自动 return this

2. ES6 class(语法糖)

let peopleList = []
const ageList = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]

class People {
  age = 0 // 定义属性 默认值:0
  constructor(age) {
    this.age = age
  }
  getDoubleAge() {
    return this.age * 2
  }
}
for (let i = 0; i <= 11; i++) {
  peopleList[i] = new People(ageList[i])
}