Created
November 10, 2020 20:03
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React hook utilising setTimeout and exposing pause, resume and cancel callbacks
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import { useCallback, useEffect, useRef } from 'react'; | |
type UseTimeoutCallback = (...args: Array<any>) => void; | |
/** | |
* Set a timer, which executes a function once the timer expires. Exposes pause, resume and cancel | |
* callbacks to the consumers. | |
* | |
* @param {UseTimeoutCallback} fn Callback function to execute after the specified timeout | |
* @param {number} ms Timeout in milliseconds after which to execute the callback | |
*/ | |
export const useTimeout = (fn: UseTimeoutCallback, ms: number) => { | |
// Indicates if timer is currently running | |
const isRunning = useRef(false); | |
// Number of milliseconds remaining before the timer runs out and callback is executed | |
const msRemaining = useRef(ms); | |
// Time when the most recent execution was requested (0 if time is not currently running) | |
const timeStarted = useRef(0); | |
// Timeout handle | |
const handle = useRef(0); | |
// Original callback function | |
const callback = useRef(fn); | |
/** | |
* Completely cancel the execution of the callback function | |
*/ | |
const cancelTimeout = useCallback(() => { | |
// Ignore request if there is no active timeout to cancel | |
if (handle.current <= 0) { | |
return; | |
} | |
// Mark timer as paused and reset all internal values to avoid being able to restart it | |
isRunning.current = false; | |
msRemaining.current = 0; | |
timeStarted.current = 0; | |
clearTimeout(handle.current); | |
handle.current = 0; | |
}, []); | |
/** | |
* Resume timeout countdown | |
*/ | |
const resumeTimeout = useCallback(() => { | |
// Ignore request if time is already running or if there is no time remaining | |
if (isRunning.current || msRemaining.current <= 0) { | |
return; | |
} | |
// Mark timer as running and record the current time for future calculations | |
isRunning.current = true; | |
timeStarted.current = Date.now(); | |
// Schedule timeout | |
handle.current = setTimeout(() => { | |
// Clear all internal values when the timer executes | |
cancelTimeout(); | |
// Invoke the callback function | |
callback.current && callback.current(); | |
}, msRemaining.current); | |
}, [cancelTimeout]); | |
/** | |
* Pause current countdown | |
*/ | |
const pauseTimeout = useCallback(() => { | |
// Ignore request if timer is not currently running | |
if (!isRunning.current) { | |
return; | |
} | |
// Mark timer as paused, clear last time started and reduce the number of remaining | |
// milliseconds by the time that passed since the last "start" call | |
isRunning.current = false; | |
msRemaining.current -= Date.now() - timeStarted.current; | |
timeStarted.current = 0; | |
// Clear timeout handle to avoid the function executing while timer is paused | |
clearTimeout(handle.current); | |
handle.current = 0; | |
}, []); | |
// Update callback function reference when a new function is passed in | |
useEffect(() => { | |
callback.current = fn; | |
}, [fn]); | |
// Start the timer on mount and cancel it on unmount | |
useEffect(() => { | |
resumeTimeout(); | |
return cancelTimeout; | |
}, [cancelTimeout, resumeTimeout]); | |
return { | |
cancelTimeout, | |
pauseTimeout, | |
resumeTimeout, | |
}; | |
}; |
@GustavoHenriqueAP Glad to hear that even 4 years later it helped someone :)
You're the best man, thanks for this gist :D
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This gist save me! haha. Thank you so much.