第166题 实现简易版jQuery

    class jQuery {
      constructor(selector) {
        const result = document.querySelectorAll(selector)
        const length = result.length
        for (let i = 0; i < length; i++) {
          this[i] = result[i]
        }
        this.length = length
        this.selector = selector
      }
      get(index) {
          return this[index]
      }
      each(fn) {
        for (let i = 0; i < this.length; i++) {
          const elem = this[i]
          fn(elem)
        }
      }
      on(type, fn) {
        return this.each(elem => {
          elem.addEventListener(type, fn, false)
        })
      }
      // 扩展很多 DOM API
    }
    
    // 插件
    jQuery.prototype.dialog = function (info) {
      alert(info)
    }
    
    // “造轮子”
    class myJQuery extends jQuery {
      constructor(selector) {
        super(selector)
      }
      // 扩展自己的方法
      addClass(className) {
    
      }
      style(data) {
          
      }
    }

    // 测试
    
    const $p = new jQuery('p')
    $p.get(1)
    $p.each((elem) => console.log(elem.nodeName))
    $p.on('click', () => alert('clicked'))