Contributing to rxjs

RxJS 9 is a platform-based generation, not an incremental RxJS 7 port. Before changing source or public behavior, read the repository charter, architecture, decisions, active project plan, open questions, and compatibility policy under ../../docs/rxjs-next.

Architectural rules

• Preserve a conforming native Observable; initialize the fallback only when the realm does not already supply one.
• Export exact, module-owned Symbols and install RxJS behavior only at those keys. Do not add string-named RxJS methods or use Symbol.for for public operators.
• Keep platform sharing semantics separate from ColdObservable and other explicit producer-per-subscription contracts.
• Base cancellation and teardown on AbortSignal and Subscriber lifecycle.
• Treat the source-pinned RxJS 7 corpus as classified migration evidence. Do not revive unsupported internals merely to turn an intentional divergence green.
• Update package-local documentation with public exports, lifecycle, distribution, or release-gate changes.

Fast checks

From the repository root:

pnpm --filter rxjs exec vitest --run src
pnpm --filter rxjs run test:types
pnpm --filter rxjs run test:package
pnpm run test:kernel
pnpm run release:check

Use pnpm --filter rxjs run test:watch for focused development. Run the narrowest relevant browser, performance, or WPT gate for changes that affect those contracts; the commands and exact matrix are in docs/RELEASE_GATES.md.

The cold and fallback ported audits intentionally retain reviewed lifecycle and arbitrary-subscribable divergences. A raw nonzero all-mode result does not authorize weakening platform semantics or hiding cases behind skips.

Project-plan discipline

The active queue is ../../docs/rxjs-next/PROJECT_PLAN.md. Work on its sole NEXT item unless the user changes priority or a small prerequisite is required. Completion requires evidence and a session-log entry, not only a source change.