javascript原型链图解的总结和实践

class People {
  constructor(props) {
    this.name = props.name;
  }
  run() {
    console.log('run')
  }
}

let lisi = new People('李四')

class Hero extends People {
   constructor(props) {
    super(props);
    this.power = props.power
   }
   heyHa() {
       alert(this.power)
   }
}

let Jinx = new Hero({ name: 'jinx', power: 'cannon!' })

Jinx.heyHa() // cannon!
// 当自身有该方法时
Jinx.run = () => console.log('i just fly!')
Jinx.run() // i just fly!

class JQuery {
  constructor(selector, nodeList) {
    const res = nodeList || document.querySelectorAll(selector);
    const length = res.length;
    for (let i = 0; i < length; i++) {
      this[i] = res[i]
    }
    this.length = length;
    this.selector = selector;
  }
  eq(index) {
    return new JQuery(undefined, [this[index]]);
  }
  each(fn) {
    for(let i = 0; i < this.length; i ++) {
      const ele = this[i]
      fn(ele)
    }
    return this;
  }
  on(type, fn) {
    return this.each(ele => {
      ele.addEventListener(type, fn, false)
    })
  }
  // 扩展其他 DOM API
}
const $$ = (selector) => new JQuery(selector);
$$('body').eq(0).on('click', () => alert('click'));