How to use `JsonObject`? about type-fest

[sindresorhus]

It types the response as strict as it possibly can without knowing anything about it other than that it's JSON. For example, json.a could be null, in which case, json.a.b would not exist.

[sindresorhus]

I think we should document in the type that it's not meant as a response type, but rather to make certain input strict.

It could maybe also be useful as a super-type for response types. So you do CustomResponseType extends JsonObject { … } to ensure you don't accidentally use non-JSON compatible types. Thoughts?

[fregante]

json.a could be null, in which case, json.a.b would not exist

GraphQL guarantees that already, if you check for json.errors first.

How am I gonna type this without // @ts-ignore and node: any? 😰

let authors: Author[] = json.repository.pullRequest.commits.nodes
	.map(node => node.commit.author); // from Refined GitHub

[BendingBender]

I think this type is useful for APIs that want to accept only JSON-like structures, it is not really useful as a response type. There you usually have an idea of how a response is structured.

For your specific example, how should TS know something about the semantics of GraphQL? If you already know the shape of your response, why do you want to use JSONObject?

[fregante]

It seemed to make sense that a fetchApi would return a JsonObject, but it's hard to even cast that as something else (see as UserInfo in the commit above) because each level "could be string or null", so in most cases you'd have to cast as unknown as UserInfo at best, which means JsonObject is lost instantly.

In the specific case I'm ok with the code throwing if a level isn't there, so the error isn't swallowed by some if levelX !== undefined, hence the as any.

I understand why TS throws, but I don't know how/if it can be used in this case.

[BendingBender]

I think it just doesn't meant to be used like this. This is only useful for APIs like JSON.stringify and the like.