[ESLint] Warn about setState directly in dep-less useEffect #15184
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
gaearon
changed the title
gaearon
commented
Mar 21, 2019
| @@ -468,9 +468,101 @@ export default { | |||
| }, | |||
| ); | |||
|
|
|||
| // Warn about assigning to variables in the outer scope. | |||
| // Those are usually bugs. | |||
There was a problem hiding this comment.
This code just moved from below with no changes.
gaearon
commented
Mar 21, 2019
| if (!declaredDependenciesNode) { | ||
| // Check if there are any top-level setState() calls. | ||
| // Those tend to lead to infinite loops. | ||
| let setStateInsideEffectWithoutDeps = null; |
Details of bundled changes.Comparing: 78968bb...78de1f3 eslint-plugin-react-hooks
Generated by 🚫 dangerJS |
threepointone
approved these changes
Mar 22, 2019
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This warns about the common mistake of using setState directly in an effect without a dependency list — which too easily leads to loops. This is the only case where I propose that we'd warn for dep-less useEffect. It looks like this:
It won't warn you about
setStatenested in another function (it'll assume you know what you're doing). Only top level ones right in the effect.It doesn't check for early returns. I considered this but then thought the pattern is still too fragile. With autofix it's not too annoying anyway.