reactjs / reactjs/react.dev

Incorrect documentation for fixing memory leaks

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JavaScript
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Description

The "isMounted is an Antipattern" documentation article suggest avoiding memory leaks with makeCancelable, but this doesn't actually solve the issue since the callback is still referenced. The garbage collector does not understand that setting hasCanceled_ means that resolve will never be called, so it cannot release resolve or the references contained within. Even if it could, reject might also reference this, so memory leaks could still exist. Instead, makeCancelable should store the resolve and reject callbacks itself, and it should null them out on cancelation.

Another user pointed this issue out in https://github.com/facebook/react/issues/5465#issuecomment-287113777

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

The affected material is the “isMounted is an Antipattern” article linked in the issue; begin by reviewing its makeCancelable example and the referenced discussion. Update the documentation so its memory-leak guidance is technically correct, then verify that the article no longer recommends the disputed implementation.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, react
Domain
documentation
Issue type
Documentation
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
35/100

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