Provide context (query key) to onError callback

[jcready]

If I want to handle errors further up the stack I don't get much context about which query had the error.

new QueryClient({
    defaultOptions: {
        queries: { onError: (err) => { /* no idea what triggered this error */ } },
        mutations: { onError: (err) => { /* no idea what triggered this error */ } },
    },
})

If the query key was provided as a second argument then I could use that to make better decisions and/or report errors with more context.

[TkDodo]

for this use case (global error handling) you can (and likely should) use the global callbacks on the queryCache instead of defaultOptions.

I've gone into details here: https://tkdodo.eu/blog/react-query-error-handling

not only will the global callbacks only be called once per cache entry (rather than once per observer), they also get the whole query / mutation passed as second parameter.

see also:

• https://react-query.tanstack.com/reference/QueryCache#global-callbacks
• https://react-query.tanstack.com/reference/MutationCache#global-callbacks