js 防抖节流

// 防抖
function debounce(func,delay){
    let timer = null
    return function(){
        let context = this
        let args = arguments
        if(timer) clearTimeout(timer)
        timer = setTimeout(()=>{
            func.apply(context,args)
        },delay)
    }
}
// 通过setTimeout实现 节流
function throttle(func,delay){
    let timer = null
    return function(){
        if(!timer){
            let context = this
            let args = arguments
            timer = setTimeout(()=>{
                timer = null
                func.apply(context,args)
            },delay||1500)
        }
    }
}
// 通过时间比较实现 节流
function throttle(func,gapTime){
    if(gapTime == null || gapTime == undefined){
        gapTime = 1500
    }
    let _lastTime = null
    return function(){
        let _nowTime = + new Date()
        if(_nowTime - _lastTime > gapTime || !_lastTime){
            func()
            _lastTime = _nowTime
        }
    }
}