经典闭包实例化，原型创建与继承

function vie(){
            var speed = 100
            return {
                getSpeed: () => speed,
                speedUp:function(){
                    speed+=10
                }
            }
        }

        console.log(vie().getSpeed())
        vie().speedUp()
        console.log(vie().getSpeed())

        var car = vie()
        car.speedUp()
        car.speedUp()
        console.log(car.getSpeed())

　原型创建与继承

function Viechel() {
    this.speed = 100;
}

Viechel.prototype.speedUp = function() {
    this.speed += 10;
}

var car = new Viechel();

1.为什么不在原型里面写function?

每一个实例对象，type属性和eat()方法都是一模一样的内容，每一次生成一个实例，都必须为重复的内容，多占用一些内存。这样既不环保，也缺乏效率，调用原型的prototype方法，是调用同一个内存地址

function Cat(name, color) {

  this.name = name;

  this.color = color;

  this.type = "猫科动物";

  this.eat = function () {
    console.log(this.name);
  };
  this.o = function () {
    console.log(this.color);
  };

}
Cat.prototype.p = function () {
  console.log(this.color);
};

var cat1 = new Cat("大毛", "黄色");

var cat2 = new Cat("二毛", "黑色");

console.log(cat1.eat == cat2.eat) // false
console.log(cat1.p == cat2.p) // true

　　

  // 1.工厂模式

  function createPerson(name, age, job) {
    var o = new Object();
    o.name = name;
    o.age = age;
    o.job = job;
    o.sayName = function () {
      console.log(this.name);
    };
    return o;
  }
  var person1 = createPerson("Nicholas", 29, "Software Engineer");
  var person2 = createPerson("Greg", 27, "Doctor");
  person1.sayName()
  person2.sayName()

　　

  // 构造函数模式

  function Person(name, age, job) {
    this.name = name;
    this.age = age;
    this.job = job;
    this.sayName = function () {
      console.log(this.name);
    };
  }
  var person3 = new Person("Nicholas", 29, "Software Engineer");
  var person4 = new Person("Greg", 27, "Doctor");
  person3.sayName()
  person4.sayName()

　　

  //原型模式

  function Person() {}
  Person.prototype.name = "Nicholas";
  Person.prototype.age = 29;
  Person.prototype.job = "Software Engineer";
  Person.prototype.sayName = function () {
    console.log(this.name);
  };
  var person1 = new Person();
  person1.sayName(); //"Nicholas" 
  var person2 = new Person();
  person2.sayName(); //"Nicholas" 
  alert(person1.sayName == person2.sayName);

　　

  //原型模式和构造函数模式组合

  function Person(name, age, job) {
    this.name = name;
    this.age = age;
    this.job = job;
    this.friends = ["Shelby", "Court"];
  }
  Person.prototype = {
    constructor: Person,
    sayName: function () {
      alert(this.name);
    }
  }
  var person1 = new Person("Nicholas", 29, "Software Engineer");
  var person2 = new Person("Greg", 27, "Doctor");
  person1.friends.push("Van");
  alert(person1.friends); //"Shelby,Count,Van" 
  alert(person2.friends); //"Shelby,Count" 
  alert(person1.friends === person2.friends); //false 
  alert(person1.sayName === person2.sayName); //true