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Debouncing with React Hooks

Gabe Ragland on January 17, 2019

Today I'm going to show you how to build a useDebounce React Hook that makes it super easy to debounce API calls to ensure that they don't execute ...

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JivkoJelev91 • Feb 24 '20 • Edited

Why not just:

export const debounce = (func, wait) => {
  let timeout;
  return function(...args) {
    const context = this;
    if (timeout) clearTimeout(timeout);
    timeout = setTimeout(() => {
      timeout = null;
      func.apply(context, args);
    }, wait);
  };
};

Now you can use this debouce in other hooks.

johanse7 • Apr 30 '20

how do you make the call debounce function ?

Dexter Marks-Barber • Jan 28 '21

const onChange = debounce(event => setQuery(event?.target?.value))

rohan2734 • May 6 '21 • Edited

nope not working , geting the state value as undefined

Dexter Marks-Barber • May 6 '21

Are you able to show your code for the event handler and how you trigger the call?

rohan2734 • May 15 '21

i have triggered the call in the same way, but it is not working at all ,and state is undefined

Michael Willian Santos • Mar 4 '20

My aproach is this way:

import { useMemo, useState } from 'react'

/**
 * Debounce a function by time
 * @param {Function} func
 * @param {Number} delay
 */

export default function useDebounce(func, delay) {
    const [id, setId] = useState(null)

    return useMemo(
        (...args) => {
            if (id) {
                clearTimeout(id)
            } else {
                setId(
                    setTimeout(() => {
                        setId(null)
                        func(...args)
                    }, delay)
                )
            }
        },
        [func]
    )
}

Gustavo • Nov 27 '20

This looks great! Could you give us an example on how to implement it?

George WL • Jan 25 '21

whilst I like the idea of this, I think the UI and the API call should be far more decoupled, so instead I've went for:

// in the useDebounce file
import { useEffect } from 'react';
/**
 * @description for use in functions with side-effects but no return value
 * @export useDebouncedFunction
 */
export default function useDebouncedFunction(handler, watchedValue, delay) {
  useEffect(() => {
    const timeoutHandler = setTimeout(() => {
      handler();
    }, delay);
    return () => {
      clearTimeout(timeoutHandler);
    };
  }, [watchedValue, delay]);
}

// in the search file
  const [searchQuery, setSearchQuery] = React.useState('');

  const fetchX = async () => {
    await getX()
      .then((updatedStock: IStockResponse) => {
        setX(updated.data?? []);
      })
      .catch(err => {
        console.error(err);
      });
  };
  useDebouncedFunction(fetchStockVehicles, searchQuery, 1000);
  const handleSearch = (value: string) => {
    setSearchQuery(value ?? '');
  };

Guilherme Baron • Sep 23 '19

Great article!

I've been using this pattern with hooks lately:

const [value, setValue] = useState()
const debouncedValue = useDebounce(value, 800)

It's clean and works well for most of the cases.

Here's a version useDebounce implemented using lodash: github.com/gnbaron/use-lodash-debo...

Hein Haraldson Berg • Apr 21 '20 • Edited

Here’s my take on a lodash.debounce hook. I don’t see why the hook shouldn’t be more convenient to use, so I basically made a useState wrapper which updates the value immediately (a requirement for controlled inputs), and updates a signal, which is meant to be used in a useEffect’s dependency array, only whenever specified as per lodash.debounce’s docs.

Tom Belton • Jul 25 '19 • Edited

Great - thanks! The example would be easier to read if you included all the imports and exports. Great job.

Gabe Ragland • Jul 25 '19

Good call! Just updated the post.

Tom Belton • Jul 25 '19

Awesome! :)

rohan2734 • May 6 '21

why dont we do this in the useEffect?

import React, { useState, useEffect } from "react";

const useDebounce = (data, delay) => {
  const [debouncedData, setDebouncedData] = useState(data);
 var timerID;
  useEffect(() => {

    if(timerID){
       clearTimeout(timerID)
    } 
    console.log("debounce executed");
     timerID = setTimeout(() => {
      setDebouncedData(data);
    }, delay);
   // return () => {
      //clearTimeout(timerID);
    //};
  }, [data.blogTitle, data.blogDescription]);

  return debouncedData;
};

export default useDebounce;

i tried this but the cleartimeout was not working, the timeout was not being cleared, i didnt understand the reason.

can anyone explain?

Giancarlos Isasi • Apr 21 '19

Thanks for share!

Igor Krupin • Nov 27 '19 • Edited

Very helpful, thank you! Years ago I needed something like this and ended up using throttle feature of redux sagas. Not bad, but I try to avoid redux (gets a bit unreadable over time).

I'm writing a new app and needed an "auto-save" feature where a form is auto-saved every x seconds, provided any of the inputs were changed. I started doing my own thing (setTimeout, setInterval) and luckily stumbled on this post. Saved me time. Elegant and it works.

Throttling API calls from UI is a very important technique to learn, I wish Facebook would throw some sort of "autocomplete" or "lookup text field" example where they use your code.

Rezuan Ahmed • Sep 14 '21

export default function useDebounce(func, delay) {
  const [timer, setTimer] = useState(null)
  return (...args) => {
    clearTimeout(timer)
    let _temp = setTimeout(() => {
      func(...args)
    }, delay)
    setTimer(_temp)
  }
}

import useDebounce from './customHooks/useDebounce'

export default function App() {
  const [val, setVal] = useState("")
  const handleSearch = useDebounce((e) => {
    // api call
  }, 100)

  return (
    <div>
      <input
        onChange={(e) => setVal(e.target.val)}
        onKeyDown={handleSearch} />
    </div>
  )
}

Nathan Foster • Jan 10 '21 • Edited

This makes the most since:

import { useCallback, useRef } from 'react'
export default function useDebounce(func, delay = 400) {
let debounce = useRef(null)
return useCallback(
(...args) => {
const context = this
clearTimeout(debounce.current)
debounce.current = setTimeout(() => {
func.apply(context, args)
}, delay)
},
[func],
)
}

Usage:

const handleWindowResize = useDebounce(SetWindow)

useEffect(() => {
window.addEventListener('resize', handleResize)

handleResize()

return () => {
  window.removeEventListener('resize', handleResize)
}

}, [])

Aaron Levin • Oct 31 '19

Hmm this doesn't seem to work if you add text after the initial query (i.e. 'wolverine' as the first full term to debounce, then appending it to become 'wolverine x-men'.. the 'x-men' part doesnt show up until the debouncing times out). I feel like this code is so short and simple I should be able to figure it out, but I can't seem to see why the UI lags so hard on the second set of characters.

Aaron Levin • Oct 31 '19

Aha, I take it back! Turns out I needed to pull my search input into its own component. Problem solved! (I think)

Matt Wright • Mar 8 '19

How could you modify this to make it a "leading" debounce?

Cezar Luiz • Feb 13 '19

Awesome! I had a similar project and this looked easier than I thought!

Guillaume Bersac • Aug 2 '19

Why using useEffect for the api call? I don't see any issue with doing async api calls inside a component rendering function.

Gabe Ragland • Aug 4 '19

Any side effects should be wrapped in useEffect or within an event handler like onClick. Not sure what could go wrong by inlining it like that, but know it’s heavily discouraged by the React team.

Jamison Dance • Nov 18 '19

You wrap side effects in useEffect so they don't run on every render. You technically could make a request inside render without wrapping it in useEffect, but it'll happen on every single render, which is usually not what you want.

You typically only want side effects to run when things they care about change, like when some search text changes. That's exactly what useEffect does for you - it helps make sure the side effects only run when they need to.

Raúl Marín • Apr 13 '20

This reply is great, thanks!

Ruchit Gandhi • Nov 16 '21

Loved the explanation. Thanks!
Although I would use useRef hook to set the timer variable to reduce the heap memory usage.

const useDebounce = (value, delay = 500) => {
  const [debouncedValue, setDebouncedValue] = useState();
  const timer = useRef(null);
  useEffect(() => {
    timer.current = setTimeout(() => {
      setDebouncedValue(value);
    }, delay);
    return () => clearTimeout(timer.current);
  }, [value, delay]);

  return debouncedValue;
};

Eran Sakal • Feb 10 '20

Hi,
Thanks for the article. I'm curious about the chosen approch of providing a value to the custom hook that gets updates over time.

export default function useDebounce(value, delay) {

Here we listen to value changes in the custom hook with the inner useEffect and react to changes. Most of the hooks I'm familiar with treat the arguments they get as sort of initialization values that doesn't change overtime or even if changed are not monitored. For example useState, useReducer, useSelector, useMemo, useCallback, useRef are all hooks that doesn't react to changes of the initial values provided to the hook.

I know that your sample works and is valid implementation but I'm sure if it will not confuse developers who read the code. you could easily expose a second argument to update the value which will look very similar to useState

wdyt?

Yevhen Kozlov • Mar 10 '20

useCallback, useSelector, useMemo, useReducer are actually operating on most recent arguments each run.
It's only useState and useRef who purposely ignore any changes on sequential calls

Yevhen Kozlov • Mar 10 '20

Amazing, did not think to have debouncedValue instead of debounced version of callback.
Probably we better cancel processing in main useEffect to avoid race conditions.

Mark Gilligan • Jan 16 '21

This was a great guide, had been struggling for a while with getting something like this to work.

Thanks!

Yaron Levi • Sep 5 '20

Thanks! Helped me a lot

Alain D'Ettorre • Jul 22 '20

You've got a missing = here

const queryString `apikey=${apiKey}&titleStartsWith=${search}`;

Uladzimir Kasacheuski • Oct 2 '19 • Edited

This is really elegant! Have you thought about publishing this as a node_module?

Chris • Aug 21 '19

Great read!
Just as a side note: you don't have to import react to your use-debounce.js.
" import { useState, useEffect } from 'react';"is just fine

Richard van den Winkel • Jan 10 '20 • Edited

Excellent!
Needed this and was struggling a bit myself to get it to work flawlessly...
Thanks!

rohan2734 • Jul 7 '21 • Edited

this is not working, i am getting redundant calls, the function calls are not getting cancelled

shakil ahmed • Aug 4 '19

Great work, thanks a lot. I want to write a similar post in my native language Bangla, is this ok if i use your post as reference and also your demo project to show how this work ?

Gabe Ragland • Aug 4 '19

Yeah sure! Please just link to my post as well somewhere.

shakil ahmed • Aug 5 '19

Thank you so much, i will.

Alex Dorosin • Apr 29 '20

thank you, kind sir!

Ruslan Baigunussov • Dec 17 '19

Try to hold down any key and you will see, that searching appears 2 times - after 500 ms after the first character and after 500 ms after the last. How to avoid this glitch?