class jQuery {

        constructor(selector) {

            const result = document.querySelectorAll(selector)

            console.log(result)

            const length = result.length

            for (let i = 0; i < length; i++) {

                this[i] = result[i]

            }

            this.length = length

        }

        get(index) {

            return this[index]

        }

        each(fn) {

            for (let i = 0; i < this.length; i++) {

                const ele = this[i]

                fn(ele)

            }

        }

        on(type, fn) {

            return this.each(ele => {

                ele.addEventListener(type, fn, false)

            })

        }

    }

    //考虑扩展性

    //插件

    jQuery.prototype.dialog = function (info){

        alert(info)

    }

    //复写机制

    class MyJQuery extends jQuery{

        constructor(selector){

            super(selector)

        }

        addClass(className){}

        style(data){}

    }

    //使用

    const jq = new jQuery('p')

    console.log(jq.get(0))

    jq.each(function(el){

        console.log(el)

    })

    jq.on('click',function(el){

        console.log(el)

    })