js class 总结

• 1.静态属性：当想给所有对象属性时，可以设置属性为静态属性，减少实例化对象体积
• 2.静态方法(单例模式)
• 3.访问器

  class Gz {
    static address = "gaoxinsilu";
    constructor(name, age) {
      this._name = name;
      this.age = age;
    }
    set name(name) {
      this._name = name;
    }
    get name() {
      return this._name;
    }
    static create(...args) {
      return new this(...args);
    }
    say(msg) {
      return this._name + this.age +
        "的地址是：" + Gz.address + ":" + msg
    }
  }
  let gz = new Gz("gz", 12);
  gz.name = "kxf";
  console.log(gz.name);
  // console.log(gz);
  // console.log(gz.say("xixi"));
  // console.log(Gz.create("gz", 12));

let data = [
      { name: "SQL", price: 121 },
      { name: "CSS", price: 111 },
      { name: "HTML", price: 101 }
    ];
    class Base {
      constructor(data) {
        this.modelData = data;
      }
      get price() {
        return this.modelData.price;
      }
      static create(data) {
        return data.map((item) => new Base(item));
      }
      static maxPrice(data) {
        return data.sort((a, b) => {
          return b.price - a.price;
        })[0].price;
      }
      static totalPrice(data) {
        return data.reduce((pre, cur) => {
          return pre + cur.price;
        }, 0);
      }
    }
    let gz = Base.create(data);
    console.log(Base.maxPrice(gz));
    console.log(Base.totalPrice(gz));

方法的重写

  let data = [
      { name: "SQL", price: 121 },
      { name: "CSS", price: 111 },
      { name: "HTML", price: 101 }
    ];
    class Base {
      constructor(data) {
        this._data = data;
      }
      show() {
        return "Base show";
      }
    }

    class Search extends Base {
      constructor(data, locator) {
        super(data);
        this.locator = locator;
      }
      info() {
        return {
          a: super.show(),
          locator: this.locator
        };
      }
      show() {
        // return super.show();
        return "@#$234";
      }
    }
    let search = new Search([], "#box");
    console.log(search.show());

• 4.使用Symbol属性保护;私有属性private

 class Gz {
   #url = "http://www.w3.org/"
   static address = "陕西省"
   constructor(name, age) {
     this.name = name;
     this.age = age;
     this[protecteds] = {}
     this[protecteds].cname = "haha"
   }
   static create(...args) {
     return new this(...args);
   }
   set cname(value) {
     this[protecteds].cname = value
   }
   get cname() {
     return this[protecteds].cname
   }
   get address() {
     return Gz.address
   }
   get url() {
     return this.#url
   }
   showInfo() {
     return this.name + ":" + this.age;
   }
 }

 let gz = Gz.create()
 console.log(gz)


 class User {
   constructor() { }
   show() {
     return this.name
   }
 }

 class Person extends User {
   constructor(name) {
     super()
     this.name = name
   }
 }
 let pp = new Person("gz")
 console.log(pp)```