status should not be success when passing a falsy query key

[kamranayub]

Related to #360 and #144

Currently when passing a falsy query key (or if the query is manual), status is being set to success. I would argue this is misleading because I think the intent of a success status should be if the query was fetched and had data (or if it has initialData). I left a comment with some thoughts on this behavior: #144 (comment)

The use case is just knowing whether the query was successfully fetched.

Proposal

Would you be open to proposing a new status, something like initial, idle, or ready? That would make these kinds of checks easier without the need to check multiple things.

States:

• ready - NEW If the queryFn has not been invoked yet, such as when passed a falsy query state or in manual mode without initial data.
• success - If the query has received a response with no errors and is ready to display its data. The corresponding data property on the query is the data received from the successful fetch. If the query is manual and has initialData set.
• loading - same as-is
• error - same as-is

Current Workarounds

I think in order to actually know whether a query has been invoked and was successful for sure with the way things currently are, we'd need to track isFetching and ensure it was true once before checking status. We could also check whether data is undefined, presumably if there was successful data, we'd have a response available (in an error, status === 'error' so that's fine). I don't know if that's always 100% the case since maybe a queryFn could be invoked and return undefined as a valid result.

[tannerlinsley]

• The next major version of React Query will have this missing idle state. It's a breaking change, so I'm not taking it lightly or rushing it.
• You can work around this by wrapping useQuery, detecting this state, and decorating the return value to have it.

[kamranayub]

Thanks, I already have a fix for our use cases, good to know! Feel free to close or leave open until resolved in v2. Aside: is there details anywhere about what to expect in v2? Exciting!

…

On Thu, Apr 30, 2020, 10:44 AM Tanner Linsley ***@***.***> wrote: - The next major version of React Query will have this missing idle state. It's a breaking change, so I'm not taking it lightly or rushing it. - You can work around this by wrapping useQuery, detecting this state, and decorating the return value to have it. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#426 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAEJU23RADAVIKGVUJFAARLRPGMG3ANCNFSM4MVWHX6A> .

[tannerlinsley]

Probably not for a while :) There's not much necessitating it right now, but we'll see.