React Essentials · Data Fetching · Lesson 20 of 26
Refetching on User Action
Concept
Refetching on User Action
You can trigger a new fetch whenever a dependency, like a search query, changes, or manually on a button click.
By the end of this lesson
- Explain the core idea behind Refetching on User Action.
- Predict output before running a change.
- Test one realistic and one unusual input.
- Use the result to make the next decision.
How to study this page
- 1. Read one concept.
- 2. Change the example.
- 3. Run, compare, and explain.
- 4. Complete the challenge below.
ExampleRunnable
useEffect(() => {
fetch("/api/search?q=" + query).then((res) => res.json()).then(setResults);
}, [query]);Self-check before continuing
Without looking at the example, describe what changes when you modify one input in Refetching on User Action. Then reopen the editor and prove your explanation with a small test.
You are ready to continue when you can predict, test, and explain the result.
Your turn
Explain what would happen if query were left out of the dependency array.
Loading editor…
Console