sindresorhus/type-fest

Proposal: `AsyncFunction`

Open

#121 opened on Aug 18, 2020

View on GitHub
 (22 comments) (2 reactions) (0 assignees)TypeScript (471 forks)batch import
corehelp wantedtype addition

Repository metrics

Stars
 (12,328 stars)
PR merge metrics
 (Avg merge 3d 5h) (11 merged PRs in 30d)

Description

To make it easier to constrain a type to be an async function. We can currently do T extends Function, but there's no way to enforce it to be async.

We already have an internal type for this:

https://github.com/sindresorhus/type-fest/blob/78019f42ea888b0cdceb41a4a78163868de57555/source/async-return-type.d.ts#L3

But I'm thinking it could be more reusable:

type AsyncFunction<Arguments extends readonly any[] = readonly any[], ReturnValue = unknown> = (...arguments_: Arguments) => Promise<ReturnValue>;

Thoughts?

Contributor guide

Research direction
Review existing AsyncReturnType and create the public AsyncFunction type as defined in the issue. Ensure it works with any arguments and return type. Add tests and documentation.
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.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Under 1 hour
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
TypeScript
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75