wait-for-timers/dist/index.js

Wait for queue of timers (e.g. requestAnimationFrame, requestIdleCallback, setTimeout) to complete before calling a callback

/**
 * Wait for a queue of sequential timers to complete before calling
 * a callback. Returns cancellation function to abort queue.
 * @param timerQueue Array of timers:
 * - "raf" -> requestAnimationFrame
 * - "ric" -> requestIdleCalback
 * - {number} -> setTimeout
 * @param onComplete Called after queue of timers completes
 * @returns Cancellation function that can be called to abort queue
 */
export default function waitForTimers(timerQueue, onComplete) {
    // Cancel current timer (gets overridden as timer changes)
    let cancelTimer = () => { };
    // Process first timer in queue
    nextTimer(0);
    return () => cancelTimer();
    function nextTimer(index) {
        // All timers have completed
        if (index >= timerQueue.length)
            return onComplete();
        const timer = timerQueue[index];
        const startNextTimer = () => nextTimer(++index);
        if (typeof timer === 'number') {
            cancelTimer = getTimers().timeout(startNextTimer, timer);
        }
        else {
            cancelTimer = getTimers()[timer](startNextTimer);
        }
    }
    function getTimers() {
        return {
            raf: (fn) => {
                const rafId = requestAnimationFrame(fn);
                return () => cancelAnimationFrame(rafId);
            },
            ric: (fn) => {
                const ricId = requestIdleCallback(fn);
                return () => cancelIdleCallback(ricId);
            },
            timeout: (fn, timeoutMs) => {
                const timeoutId = setTimeout(fn, timeoutMs);
                return () => clearTimeout(timeoutId);
            },
        };
    }
}