Use Partial<TData> rather than TData | {}

[tgriesser]

This is related to the changes in #1983 - I think Partial<TData> better captures the intent of the change and plays much nicer with TypeScript, intellisense autocompletion, etc.

[hwillson]

Great idea @tgriesser - thanks very much!

[donataswix]

Not sure why Partial<TData> was approved. This basically overrides whatever people used as their (carefully crafted) TData concrete type and is definitely not equivalent to TData | {}.

[rosskevin]

I agree with @donataswix - use of Partial makes all properties optional and is not correct.

@hwillson we should get a patch out asap as this is a breaking change to all users who are strongly typed, I'll put up the PR now.

[tgriesser]

Yeah, I think main issue here was the change to TData | {} in #1983 was breaking in the first place, this was just a band-aid on that from a typing perspective since {} is effectively an any in TS.

Keeping TData | undefined and a boolean flag as to whether data has been returned (I believe I saw this mentioned elsewhere) feels like it would be the best solution here.