function debounce(fn, delayTime) {
            let timer = null;
            return function () {
                let args = arguments;
                let context = this;
                clearTimeout(timer)
                timer = setTimeout(() => {
                    fn.apply(context, args)
                }, delayTime)
            }
        }

function throttle(fn, delayTime) {
            let pre = null
            return function () {
                let args = arguments;
                let context = this;
                let now = Date.now()
                if (now - pre >= delayTime) {
                    fn.apply(context, args)
                    pre = now
                }
            }
        }

function throttle(fn, delayTime) {
            let timer = null
            return function () {
                let args = arguments;
                let context = this;
                if (!timer) {
                    setTimeout(() => {
                        fn.apply(context, args)
                        timer = null;
                    }, delayTime)
                }
            }
        }