防抖和节流函数实现
1.手写防抖
function debounce(handleEvent, time, flag){
    let timeout = null;
    return function(...agrs){
        clearTimeout(timeout)
        if(flag && !timeout){
            handleEvent.apply(this, args)
        }
        timeout = setTimeout(()=>{
            handleEvent.apply(this, args)
        },time)
    }
}2.手写节流
function throttle(handleEvent, time){
    let timer = null;
    return function(...args){
        if(!timer){
            timer = setTimeout(() => {
                timer = null;
                handleEvent.apply(this, args)
            }, time);
        }
    }
}