Fix return type of database extension store method

[haines]

This PR changes the type of the database extension's store method from

(data: storePayload) => void

to

(data: storePayload) => Promise<void>

to make it clear that the function is expected to be asynchronous and will be awaited in the onStoreDocument hook.

Also, instead of returning the promise directly from the extensions onStoreDocument, it is now awaited to ensure that the call stack on any error is correct.

[GermanJablo]

@janthurau and @haines

Could there be something wrong with this PR? if I do

store: (data) => { return; }, I get the error:

Type 'void' is not assignable to type 'Promise'

and if I do:

store: async (data) => { return Promise.resolve();}, I get the error:

Promise-returning function provided to property where a void return was expected. (eslint@typescript-eslint/no-misused-promises)

[haines]

Using an async function is correct. I think the linter is complaining because you are returning something unnecessarily. Try this:

store: async (data) => { await Promise.resolve(); }

Technically for a no-op I think you could just do

store: async (data) => { }

but the linter will probably complain about that too.

[GermanJablo]

Yeah, I tried those two too and a few other combinations. The linter always complains:

store: async (data) => void {},
store: async (data) => {},
store: async (data) => await Promise.resolve(),
store: async (data) => { await Promise.resolve(); }
store: async (data) => { return Promise.resolve(); }

I don't understand what's going on here. Can you reproduce the error if you enable eslint@typescript-eslint/no-misused-promises?

[haines]

I'm afraid I'm travelling at the moment so I can't check if I can reproduce for a few days.

I would maybe try explicitly providing the return type like

store: async (data): Promise<void> => { await Promise.resolve(); }