SOURCE

//防抖
function debounce(fn, delay = 100) {
    let timer
    return function () {
        if (timer) {
            clearTimeout(timer)
        }
        const args = arguments
        timer = setTimeout(() => {
            fn.apply(this, args)
        }, delay)
    }
}
// 节流
function throttle(fn, delay = 200) {
    let flag = true
    return function () {
        if (!flag) return
        flag = false
        const args = arguments
        setTimeout(() => {
            fn.apply(this, args)
            flag = true
        }, delay)
    }
}