Debouncing requests with React Query

Unnecessary requests generate an overload that charges a high price from those who serve data as well as from those who consume them, since both parts waste resources transmitting data that won't be used.

One of the most popular strategies to avoid unnecessary requests is called debouncing. According to the Wiktionary, the term joins de + bounce and means:

To discard events or signals that should not be processed because they occurred too close together.

A frequent case of a bounce that fires unnecessary requests is filtering a list by a term. If the term has 5 letters, and one request occurs at every letter typed, 4 requests were meaningless and, therefore, should have been prevented.

The React Query library offers some benefits for those who need to manage requests within a React application. By default, it prevents simultaneous requests to the same resource and is able to cache responses as easily as passing a simple parameter to the query.

However, debouncing is an advantage not brought by React Query, unfortunately. So we need to wrap it in a simple abstraction able to satisfy that necessity too. The following example suggests a way of extending React Query to add the new functionality with little more than twenty lines of code:

import { useState, useEffect } from 'react';
import { useQuery } from 'react-query';

export const useCustomQuery = (
  { debounce, ...options } = {}
) => {
  const [newParams, setNewParams] = useState(params);
  const stringify = obj => JSON.stringify(obj);

  useEffect(() => {
    if (stringify(params) !== stringify(newParams)) {
      const timerId = setTimeout(
        () => setNewParams(params),
      return () => clearTimeout(timerId);
  }, [params]);

  return useQuery(newParams, request, options);

In this gist, you find an index.html containing all the necessary code to try the above implementation locally.

An animation containing two Safari windows. The first one filters a list without debouncing. The second one does the same, but with deboucing
Without debounce (left). With debounce (right).

The animation above shows the power of debouncing in practice. Without it (window at left), the application fires 12 requests and exchanges 28.3 KB of data. With it (window at right), the application fires only 1 request and exchanges 294 B. A total saving of 91% in requests and 99% in transmitted data.

To learn more about Rect Query, visit its official website.

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