QOL: throw error on invalid backend parameter

[KonradHoeffner]

I made the mistake of using backend:memdown instead of backend:memdown()in the constructor of Quadstore:

...
import memdown from "memdown";
const store = new Quadstore({ backend:memdown, comunica: newEngine(), dataFactory: DataFactory});
...
await store.open();

However this only throws an error when calling store.open:

throw new Error(`Store is not ready (status: "${this.db.status}"). Did you call store.open()?`);
                  ^
Error: Store is not ready (status: "undefined"). Did you call store.open()?

And the error message does not point out that the db is in the wrong format. It would be helpful if the constructor would throw an error that the backend is invalid.

[jacoscaz]

Very good point @KonradHoeffner . I'll happily take a PR if you're able to but will do this myself if not. It's little things like this that cumulatively make life a lot easier for developers.

By the way, if you feel comfortable doing so, I'd be interested in hearing about your use-case for quadstore. Either privately or at https://github.com/beautifulinteractions/node-quadstore/discussions/112 .

[KonradHoeffner]

I'm unfortunately not familiar enough with the codebase to create a PR but I shared our use case in #112, thanks!

[jacoscaz]

Done, will be included in the next version.