KeysOfType

Description

  type KeysOfType<T, U> = {
    [K in keyof T]: T[K] extends U ? K : never;
  }[keyof T];

Contributor guide

Tech stack

typescript

Domain

developer experience

Issue type

feature

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

3

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

1-3 hours

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

stale

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

needs investigation

Prerequisites

TypeScript genericsconditional typescontributing guidelines

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

45

Research direction

Examine other utility types in the type fest source to follow the same pattern (e.g., index.ts, source/ directory). Write tests in the test d directory. Consider adding documentation in readme. Engage with maintainers via comments to confirm the type signature and naming.