Debounce & Throttle

debounce_throttle.js

debounce = (delay, cancel) => (listener, wait) => {
    let delayId

    return function(...args) {
        cancel(delayId)
        return delayId = delay(() => listener.apply(this, args), wait)
    }
}
debounceTimeout = debounce(setTimeout, clearTimeout)
debounceAnimationFrame = debounce(requestAnimationFrame, cancelAnimationFrame)

throttle = (delay, cancel) => (listener, wait) => {
    let throttling
    let delayId
    let before

    return function(...args) {
        const now = Date.now()

        if (!throttling) {
            listener.apply(this, args)
            before = now
            throttling = true
        } else {
            cancel(delayId)

            return delayId = delay(() => {
                if (now - before >= wait) {
                    listener.apply(this, args)
                    before = now
                }
            }, wait - now - before)
        }
    }
}
throttleTimeout = throttle(setTimeout, clearTimeout)