js防抖和节流

防抖 一定时间间隔后再触发

节流 一定时间内只能触发一次

 

防抖

var debounce = function debounce(fn, delay) {

            let timer = null;

            return function () {

                let args = arguments; let context = this;

                if (timer) {

                    clearTimeout(timer);

                    timer = setTimeout(function () {

                        fn.apply(context, args);

                    }, delay);

                } else {

                    timer = setTimeout(function () {

                        fn.apply(context, args);

                    }, delay);

                }

            }

        }

 

节流 

var throttle = function throttle(fn, delay) {

            let timer = null,

                remaining = 0,

                previous = new Date();

            return function () {

                let now = new Date(),

                    remaining = now - previous,

                    args = arguments,

                    context = this;

                if (remaining >= delay) {

                    if (timer) {

                        clearTimeout(timer);

                    }

                    fn.apply(context, args);

                    previous = now;

                } else {

                    if (!timer) {

                        timer = setTimeout(function () {

                            fn.apply(context, args);

                            previous = new Date();

                        }, delay - remaining);

                    }

                }

            };

        }