JS函数防抖节流

函数防抖debounce：(多次操作合并为一次)

function debounce (fn,delay) {
    var timer = null;
    return function (e) {
        clearTimeout(timer);
        timer = setTimeout(() => {
            fn.apply(this,argument);
        },delay)
    }
}

函数节流throttle：(一定时间内只触发一次)

function throttle(fn,delay) {
    let canRun = true;
    return function () {
        if(!canRun) return;
        canRun = false;
        setTimeout(() => {
            fn.apply(this,arguments);
            canRun = true;
        },delay);
    }
}