zloirock/core-js

Health v2 · maintenance only

Adoption not part of the score

25526 stars · 1686 forks observed · 2026-08-28

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

core-js is a modular JavaScript standard library providing polyfills for ECMAScript features up to 2025, TC39 proposals, and some WHATWG/W3C web standards like URL. It supports importing only needed features, pollution-free usage via core-js-pure, and automatic injection through tools like Babel and SWC.

Use cases

• use modern JavaScript features in older browsers
• polyfill ES2025 features and TC39 proposals
• make code run consistently across browsers with engine bug fixes
• reduce bundle size by importing only required polyfills
• use polyfills without polluting the global namespace
• support new Set, Iterator, and Promise methods in older engines

When to choose

• you need maximum ECMAScript coverage across old and new engines
• you want strict spec compliance and engine bug workarounds
• you use Babel or SWC and want automatic polyfill injection
• you need to polyfill early-stage TC39 proposals

When to avoid

• you target only evergreen browsers and need no polyfills
• you want a minimal runtime with zero library overhead
• you need polyfills for non-JavaScript languages

Facets

library · maturity active

sdk developer-tools plugin-system web-development frontend programming-languages cross-platform browser bun cross-platform polyfill javascript ecmascript esnext shim ponyfill babel compatibility standard-library nodejs web-server deno

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