rxjs
Reactive Extensions for modern JavaScript
About
Reactive Extensions for modern JavaScript
Live mirror of the GitHub README. Updated whenever the repo's default branch changes.
RxJS: Reactive Extensions For JavaScript
RxJS 8 Monorepo
Look for RxJS and related packages under the /packages directory. Applications like the rxjs.dev documentation site are under the /apps directory.
Reactive Extensions Library for JavaScript. This is a rewrite of Reactive-Extensions/RxJS and is the latest production-ready version of RxJS. This rewrite is meant to have better performance, better modularity, better debuggable call stacks, while staying mostly backwards compatible, with some breaking changes that reduce the API surface.
Versions In This Repository
- master - This is all of the current work, which is against v8 of RxJS right now
- 7.x - This is the branch for version 7.X
- 6.x - This is the branch for version 6.X
Most PRs should be made to master.
Important
By contributing or commenting on issues in this repository, whether you've read them or not, you're agreeing to the Contributor Code of Conduct. Much like traffic laws, ignorance doesn't grant you immunity.
Development
Because of this issue we're using yarn. (Basically the docs app uses @types/jasmine, and the package uses @types/mocha and they get hoisted to the top level by npm install with workspaces, and then TypeScript vomits everywhere when you try to build).
cdto the repository rootyarn installto install all dependenciesyarn workspace rxjs testwill run the RxJS test suiteyarn workspace rxjs.dev startwill start the rxjs.dev documentation site local development server
Quick facts
npm install rxjsHow Sourcemap Explorer detects rxjs
We catch rxjs from two complementary signals: bundled source paths and the embedded package.json. Modern bundlers (webpack, Vite, esbuild, Rollup, Turbopack) preserve the original node_modules/rxjs/ paths inside the JavaScript sourcemap's sources[] array — that's the canonical signal. When the matching package.json is also captured in sourcesContent[], we read the exact version field — patch number included. No regex guessing, no version inference.
- 1
Confirm the site exposes sourcemaps
In DevTools Network, check the response headers of any application script for `SourceMap` or `X-SourceMap`. Failing that, fetch the script's last 4 KB and look for a `//# sourceMappingURL=` comment.
- 2
Find the package in the bundle
Open DevTools → Network → reload. Click any application script and look at its sourcemap. Inside, search `sources[]` for entries matching `node_modules/rxjs/` — every match confirms the package is bundled. The matching `sourcesContent[i]` for `node_modules/rxjs/package.json` gives you the exact installed version.
- 3
Read the version directly from package.json
Run `jq -r '. as $m | $m.sources | to_entries[] | select(.value | endswith("node_modules/rxjs/package.json")) | $m.sourcesContent[.key] | fromjson | .version' bundle.js.map`. Sourcemap Explorer automates the same query in the popup.
Recent versions
FAQ
What is rxjs used for?
Reactive Extensions for modern JavaScript
How can I tell if a website is using rxjs?
Open the page in Chrome with the Sourcemap Explorer extension installed and read the Stack tab. We catch `rxjs` from two complementary signals: `node_modules/rxjs/` paths inside the JavaScript sourcemap, and the embedded `package.json` we read for exact-version detection. Without the extension you can do the same lookup manually in DevTools — the steps are listed in the "How Sourcemap Explorer detects" section above.
What is the latest version of rxjs?
7.8.2, as published on the npm registry. The "Recent versions" table on this page lists the most recent 8 releases with their release dates. Sourcemap Explorer reports the version actually bundled into a site, which can lag the latest release by months on real-world deployments.
Where can I read more?
Project homepage: https://rxjs.dev. Source code: https://github.com/reactivex/rxjs. Published on npm: https://www.npmjs.com/package/rxjs. Licensed as Apache-2.0.
Detected by Sourcemap Explorer
When a bundle ships sourcemaps, we read the embedded package.json for rxjs and report the precise version. Without sourcemaps, an import / require in the page's scripts is enough to flag it.