Front-end performance optimization-anti-shake throttling

Anti-shake and throttling are common methods used for performance optimization during front-end development:

Anti-shake function (debounce):

 function _debounce(fn, delay) {

    var delay = delay || 200;
    was hours;
    return function () {
        var th = this;
        var args = arguments;
        if (timer) {
            clearTimeout (timer);
        }
        timer = setTimeout (function () {
            timer = null;
            fn.apply (th, args);
        }, delay);
    };
}
 

Throttle function (throttle):

function _throttle(fn, interval) {
    var last;
    var timer;
    var interval = interval || 200;
    return function () {
        var th = this;
        var args = arguments;
        var now = +new Date();
        if (last && now - last < interval) {
            clearTimeout(timer);
            timer = setTimeout(function () {
                last = now;
                fn.apply(th, args);
            }, interval);
        } else {
            last = now;
            fn.apply(th, args);
        }
    }
}