fix: Support nodejs v8 promise typing

[alexkvak]

No description provided.

[drwatsno]

Wait.. I think it will break someone who already using this typings 🤔

[drwatsno]

Anyway, could someone please explain this Pick<Promise<T>, "then" | "catch" | "etc"> typing? It looks confusing

[alexkvak]

@kibertoad I guess the solution of #3422 was wrong.

Could you explain why the previous version
interface ChainableInterface<T = any> extends Promise<T>
does the wrong things?

[lorefnon]

@alexkvak can you please provide some context on what are you trying to fix ?

Wait.. I think it will break someone who already using this typings 🤔

Yes, finally will not be available in QueryInterface where as it is exposed.

[alexkvak]

I try to return node v8 support.
If you create new project from scratch with @types/node@8 and latest knex version, you become Typescript compile error.

Sorry, I can’t provide some code just node.

[lorefnon]

Could you explain why the previous version
interface ChainableInterface<T = any> extends Promise
does the wrong things?

So, typescript interfaces are mutable. And it is possible for other packages (like @types/bluebird-global as was the case in #3422) to extend global interfaces and add keys etc. You can read more about this feature here.

ChainableInterface (what knex.select etc. returns) is not a Promise, but it exposes some promise methods which get delegated to the resolved promise when invoked.

When this happens then ChainableInterface extends Promise is wrong because it claims that it is compatible with Promise but in reality it is not. It is only exposing a subset of the methods. (Essentially you are claiming its domain is a superset where as its actually a subset)

This is usually not a problem in practice, but one case in particular (timeout) is problematic because Bluebird's timeout doesn't match the signature of an identically named function implemented in Knex.

There shouldn't really be a conflict because Bluebird's timeout is not actually available through QueryInterface even if it was the global Promise. But the conflict arises because of the lax type definition of QueryInterface.

Anyway, could someone please explain this Pick<Promise, "then" | "catch" | "etc"> typing? It looks confusing

@drwatsno

It is conceptually similar to Lodash.pick. You get only the keys that you pick mapped to the corresponding values:

type A = { a: string, b: string, c: string }
type B = Pick<A, "a" | "b">;
// Same as: 

type B = { a: string, b: string }

[lorefnon]

@alexkvak Can you please share the error that you get ?

[alexkvak]

@lorefnon thanks!

[kibertoad]

Released in 0.20.2