Handling API errors

[avalladaresm]

Is there a specific way to handle error messages from Expressjs for example?
Say I do res.status(404).send({message:'this is the error message'}), is there a way to get that message on the onError callback using the useMutation hook? All I get from the error is a default error message Request failed with status code 404.

[TkDodo]

Can you create a codesandbox example maybe? Happy to look into it 😊

[avalladaresm]

Well... It's actually a bit hard to explain now... I was just finishing the codesandbox example to post it here and figured it out by looking it here. It seems it wasn't a react-query issue, more like me not knowing how to exactly get the custom error message from axios, in which case, the way to get it on the onError callback on the useMutation hook would be

onError: (err, variables) => {
    console.log("err", err.response.data.message);
}

and what I was doing was actually console.log("err", err.message), that's why I only received Request failed with status code 404 as stated above.

Thanks for wanting to help! 😃