tj/co

Health v2 · maintenance only

Flags: no_releases

Adoption not part of the score

11841 stars · 778 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

co is a JavaScript library for Node.js and the browser that provides generator-based async control flow, letting you write non-blocking code using yield with promises, thunks, arrays, objects, and generators. It was a precursor to async/await and returns promises from co() calls.

Use cases

• write async nodejs code with generators instead of callbacks
• run multiple promises in parallel with yield on arrays or objects
• wrap generator functions into promise-returning functions
• handle async errors with try/catch in generator code
• support thunks and promises in a unified async flow

When to choose

• maintaining legacy Node.js codebases that predate async/await
• running on very old Node versions or browsers without async/await support
• you prefer generator-based coroutine style over promise chains

When to avoid

• writing new code on modern Node.js or browsers with native async/await
• you need actively developed async tooling
• your environment lacks generator support and you don't want transpilation

Facets

library · maturity maintenance

concurrency developer-tools developer-tools backend browser async-control-flow generators coroutines promises thunks legacy-async algorithms nodejs javascript

Member repositories

For agents

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