microsoft / microsoft/TypeScript

[P in keyof T]: T[P] not accepting inferred base type via extends

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Description

TypeScript Version: 3.8.3

Search Terms:

  • [P in keyof T]?: T[P]
  • typescript generic extends in keyof
  • typescript generic extends T[P]
  • typescript mongo collection generic

Code

interface IModel {
	id: string;
}

type Query<T> = {
	[P in keyof T]?: T[P]
}

export class Base<T extends IModel> {
	public find(query: Query<T>): void {
		// Forward the query to database
		console.log(query);
	}

	public findOneById(id: string): void {
		this.find({ id });
	}
}

Expected behavior:

It's expected to allow to execute the find with the properties defined on IModel as base of any other model;

Actual behavior:

It shows an error:

Argument of type '{ id: string; }' is not assignable to parameter of type 'Query<T>'.ts(2345)

Playground Link:

https://typescript-play.js.org/#code/JYOwLgpgTgZghgYwgAgJIFkD2ATCAbZAbwCgBIYbALmQGcwpQBzAbmIF9jiwBPABxQCKAV2jcAPABUAfMgC8RMgG0ACslDIA1hG6YYyCQF0A-NQkqD7ThAAevTFDDIEeODRrIAQq4iTkNyCDY7hg4+DIkpLxCAEZ4wAjIMKDYABQAjiJQ3NTCopJSAJTUAG6YFAqkpAD0VcgAYvYA7nBQ2MhgABYoGaLtmMjYcGBw0d5kpAiYIDSYeBAAdHiYjOmZ3AWspBxkUbHxickA8iAQHtyoqRTUdAwgjEXIpeURpJ3ANPNJgSmEam1sGzIHA4QA

Related Issues:

Didn't find any related issue

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the TypeScript 3.8.3 example from the issue and its Playground link, then read the comment thread for the current consensus. No source file or test is named; the work is complete when the generic find call using the IModel property is consistently accepted or the expected behavior is clearly resolved.

Written by the indexing model from the issue text.

Assessment

Tech stack
typescript
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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