Custom hook example has missing dependency
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- Dominant language
- JavaScript
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Description
Regarding 'Building Your Own Hook' page (github link).
Small but critical mistake in custom hook example for function useFriendStatus(). It needs a dependency. I.E.
Change line 91 by inserting , [friendID].
Without the dependency this appears to be 'magic'. I found I had to add a dependency when writing my learning hook, otherwise my counter just spins indefinitely.
Example
Custom hook:
function useCounter(targetId: string) {
const [counter, setCounter] = useState(0);
useEffect(() => {
setCounter(counter+1);
}, [targetId]);
return counter;
}
Client code:
interface MainProps {
counterTargetId: string;
}
export default function MainPage(props: MainProps = {
counterTargetId: 'a',
}) {
const currentCount = useCounter(props.counterTargetId);
return (<div>
<p>
Count: {currentCount}
</p>
</div>);
}
function App() {
const [targetId, setTargetId] = useState('a');
return (
<div className="App">
<input
type="button"
value="Toggle"
onClick={() => setTargetId(targetId === 'a' ? 'b' : 'a')}/>
<MainPage counterTargetId={targetId}/>
</div>
)
}
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Open content/docs/hooks-custom.md and inspect the useFriendStatus() example around line 91. Update the example's dependency list as described, then verify the documentation renders correctly and that the example shows the intended dependency.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- javascript, react
- Domain
- documentation
- Issue type
- Documentation
- Difficulty
- 1/5
- Estimated time
- Under an hour
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 70/100