手写题

手写数组去重

1、let arr = [1,2,3,3,4,4,5,5]

function cut(arr){

    let newList = []

    for(let i = 0 ; i <arr.length;i++){
        if(newList.indexOf(arr[i]) == -1){
            newList.push(arr[i])
        }
    }
    return newList
}

let List = cut(arr)

2、let arr = [1,2,3,3,4,4,5,5]

function cut(arr){

    for(let i = 0 ; i <arr.length;i++){
        for(let j = 0 ; j <arr.length;j++){
            if(arr[i] == arr[j] && i != j){
                arr.splice(j,1)
            }
        }
    }
    return arr

}

let List = cut(arr)

手写深拷贝

1、     let obj = {
        a:{aaa:[{a:'1'},{b:'2'},{c:3}]},
        rrr:'123',
        ttt:undefined,
        yyy:null
    }

    function clone(obj){
        let newObj = {}

        for(let key in obj){
            newObj[key] = obj[key]
        }
        return newObj
    }

    let newList = clone(obj)
    
    2、
    let newList = JSON.parse(JSON.stringfly(obj))

手写发布订阅

1、//发布订阅
let eventBus = {
    arrays:{},
    on:function(type,fn){
        this.arrays[type] = this.arrays[type] || []
        this.arrays[type].push(fn)
    },
    emit:function(type,data){
        if(!this.arrays[type])return
        this.arrays[type].map((fn)=>{
            fn(data)
        })
    }

}
eventBus.on('click',function(data){
    console.log('消息订阅1：'+data);
})

eventBus.emit('click','发布啦')

手写Ajax

手写防抖(throttle) 和 节流(debounce)

1、 //防抖throttle
function throttle(){
    if(timer){
        clearTimeout(timer);
        timer = setTimeout(function(){
            number ++
            let Hthrottle = document.getElementsByClassName('Hthrottle')
            console.log(Hthrottle);
            Hthrottle.innerHTML= '防抖:'+number;
        },1000)
    }else{
        timer = setTimeout(function(){
            number ++
            let Hthrottle = document.getElementsByClassName('Hthrottle')
            console.log(Hthrottle);
            Hthrottle.innerHTML= '防抖:'+number;

        },1000)
    }

}

2、//节流debounce
function debounce(){

    if(timer){
        return
    }else{
        timer = setTimeout(function(){
            let Hdebounce = document.getElementsByClassName('Hdebounce')
            console.log(number);
            number ++
            Hdebounce.innerHmtl = '节流:'+number
            timer = null
        },1000)
    }

}

手写promise.all

手写简单版promise