React 18: Trouble with Controlled Inputs and Debouncing in a Search Component
I've been researching this but I'm stuck on something that should probably be simple..... I'm relatively new to this, so bear with me. I'm building a search component in React 18 that should debounce user input to avoid overwhelming my API with requests. I set up an input field as a controlled component, but I'm facing issues with the state not updating as expected. When I type quickly, it seems like the input doesn't reflect the latest value until a short delay, and sometimes the API call is triggered with an outdated value. Here’s the relevant part of my code: ```javascript import React, { useState, useEffect } from 'react'; const SearchComponent = () => { const [query, setQuery] = useState(''); const [debouncedQuery, setDebouncedQuery] = useState(query); useEffect(() => { const handler = setTimeout(() => { setDebouncedQuery(query); }, 300); return () => { clearTimeout(handler); }; }, [query]); useEffect(() => { if (debouncedQuery) { fetch(`https://api.example.com/search?q=${debouncedQuery}`) .then(response => response.json()) .then(data => console.log(data)); // handle data } }, [debouncedQuery]); return ( <input type="text" value={query} onChange={(e) => setQuery(e.target.value)} placeholder="Search..." /> ); }; export default SearchComponent; ``` I thought that using `setTimeout` in the `useEffect` for debouncing would work, but it seems like the `debouncedQuery` is often one step behind. For example, if I type "apple", the fetch call is triggered with no query or perhaps "app" instead of the full word. I've tried logging both `query` and `debouncedQuery` inside the useEffect, but they appear to be updating correctly. Is there a more reliable way to handle this debouncing while ensuring the input reflects the latest state immediately? Any best practices or improvements I can implement to handle this situation? What am I doing wrong? Any ideas what could be causing this? My development environment is Ubuntu 22.04. Thanks for your help in advance!