节流和防抖

1.防抖

function debounce(func, wait) {
    let timeout = null
    return function() {
        let args = arguments
        if (timeout) clearTimeout(timeout)
        timeout = setTimeout(() => {
            func.apply(this, args)
        }, wait)
    }
}

2.节流

function throttle(fn, delay) {
    let flag = true,
        timer = null
    return function(...args) {
        let context = this
        if(!flag) return
        
        flag = false
        clearTimeout(timer)
        timer = setTimeout(function() {
            fn.apply(context,args)
            flag = true
        },delay)
    }
}