What's the rationale for getQueryData() not accepting a partial queryKey?

[sam-rad]

Looking at the client api if I have some data stored with key ['x', 1]:

client.getQueryData(["x", 1]);     // this returns data
client.getQueryData(["x"]);        // this returns undefined

client.getQueriesData(["x", 1]);   // this returns data in tuple
client.getQueriesData(["x"]);      // this returns data in tuple

Why getQueriesData accepts a partial key and properly returns data but getQueryData doesn't?

[vossmalte]

Imagine: you have data for ['x',1] and ['x',2] and ['x'].
What result expect do you expect from client.getQueryData(["x"]);?

getQueriesData does accept a partial key as being part of a filter.
On the other hand, getQueryData looks up a specific cache entry (and if it does not exist, it is undefined).

[sam-rad]

All I'm saying is it's confusing that these two behave differently without any explicit mentions in the docs. Suggesting to fix the confusion there are two options:

• Make it clear in the documentation
• Make the api behave the same

[TkDodo]

return the first one

the first one of what, insertion order? It's an implementation detail that we use a Map internally. You would also get different result depending on which order the components rendered. Why would this be a good idea, and more importantly - what would it be needed for?

The difference is that getQueryData takes a key, and getQueriesData takes a QueryFilter. Yes, the key can act as a queryFilter, but that's about as far as the similarities go. We've also tried to make sure to reflect this in the naming: Functions that have a plural in their name (queries in getQueriesData) take a filter, match fuzzily and can return multiple entries. Functions that have singular (query in getQueryData) take only a key, match exactly and only return one entry or undefined.

The docs are pretty clear on this imo:

https://tanstack.com/query/v5/docs/react/reference/QueryClient#queryclientgetquerydata

getQueryData is a synchronous function that can be used to get an existing query's cached data. If the query does not exist, undefined will be returned.

vs.

https://tanstack.com/query/v5/docs/react/reference/QueryClient#queryclientgetqueriesdata

getQueriesData is a synchronous function that can be used to get the cached data of multiple queries. Only queries that match the passed queryFilter will be returned. If there are no matching queries, an empty array will be returned.

[sam-rad]

The docs says they both accept filters:

[TkDodo]

not in v5!

[sam-rad]

That's what you get when you google the api. So it would be great to clarify that this queryFilter is slightly different from the other queryFilter.