1. 創(chuàng)建一個(gè)新的空對(duì)象

2. 將構(gòu)造函數(shù)的作用域賦給新對(duì)象(this指向它）

3. 新對(duì)象增加構(gòu)造函數(shù)的基本方法和屬性。

4. 返回新對(duì)象

實(shí)現(xiàn)

function create() {
  //創(chuàng)建一個(gè)空對(duì)象
  let obj = new Object();
  //獲取構(gòu)造函數(shù)
  let Constructor = [].shift.call(arguments);
  //鏈接到原型
  obj._proto_ = Constructor.prototype;
  //綁定this值
  let result = Constructor.apply(obj, arguments); //使用apply，將構(gòu)造函數(shù)中的this指向新對(duì)象，這樣新對(duì)象就可以訪問構(gòu)造函數(shù)中的屬性和方法
  //返回新對(duì)象
  return typeof result === "object" ? result : obj; //如果返回值是一個(gè)對(duì)象就返回該對(duì)象，否則返回構(gòu)造函數(shù)到一個(gè)實(shí)例對(duì)象
}

使用

function People(name, age) {
  this.name = name;
  this.age = age;
}

//通過new創(chuàng)建構(gòu)造實(shí)例
let people1 = new People("Jack", 20);
console.log(people1.name); //Jack
console.log(people1.age); //20

//通過create方法創(chuàng)建實(shí)例
let people2 = create(People, "Rose", 18);
console.log(people2.name); //Rose
console.log(people2.age); //18