fix(types): fix MutateFunction

[jelteliekens]

TVariables now extends undefined to determine the return type of MutateFunction.

Fixes #661. When disableling --strictNullChecks undefined is always in every type's domain. undefined extends TVariables would always be true.

[MichaelDeBoey]

@all-contributors Please add @jelteliekens for code

[allcontributors]

@MichaelDeBoey

I've put up a pull request to add @jelteliekens! 🎉

[basslagter]

As I said in my issue (#661), this fix doesn't seem to be helpfull

[jelteliekens]

@basslagter It is merged with master but not yet release. v2.4.6 doesn't include this fix yet. Hopefully it does solve your issue once it get released.

[tannerlinsley]

🎉 This PR is included in version 2.4.7 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[basslagter]

Works! Thanks

[justincy]

I think that this change is making variables required when calling the mutate function, whereas previously you were able to call the mutate function without any arguments. Is that intended? The docs say arguments are optional.

[jelteliekens]

Can you give a code example? If you expect variabels in the mutate function to do your API call, isn’t it required to pass variables when calling the mutation function?

[justincy]

Yes, but not all API calls require variables and thus mutate doesn't require it either: https://github.com/tannerlinsley/react-query#returns-3

const [mutate] = useMutation(() => {
    return axiox.post('/some/url');
});

[justincy]

I don't know what the right fix is. I'm not claiming this needs to be reverted. But before this change I was able to call mutate with no args, then after the change the compiler is telling me that at least one arg is required. I deal with it by just passing undefined.

[nx-cloud]

View your CI Pipeline Execution ↗ for commit 3165838

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☁️ Nx Cloud last updated this comment at 2026-05-29 02:06:41 UTC