TypeScript type for setQueryData updater function

[ryands17]

In react-query version 2.12.1, the typescript types changed for setQueryData and it doesn't accept an undefined value anymore.

For context, this is to get the query data:

const previousTodos = queryCache.getQueryData<Todos>('todos') // returns Todos | undefined

Here, setQueryData doesn't accept undefined as the returned value:

queryCache.setQueryData<Todos>('todos', todos => previousTodos)

This gives the following TS issue:

Was this change intentional in the newer version?

This is only an issue with the updater function and not with a direct update. Doing this works fine:

queryCache.setQueryData('todos', previousTodos)

[boschni]

Hi @ryands17! When specifying setQueryData<Todos> you are basically saying the result should be of type Todos. Because setQueryData sets the query status to success, and success means the data is there, this would be correct. You could specify the result as setQueryData<Todos | undefined> to also allow undefined.