[oliverlaz]

Ticket: https://linear.app/stream/issue/REACT-1466

CLA

• I have signed the Stream CLA (required).
• Code changes are tested

Description of the changes, What, Why and How?

In v10 Event is a discriminated union, but channel.state.typing was still typed Record<string, Event>. Any custom typing indicator that reads event.user or event.parent_id stopped compiling and needed a hand-written (e): e is EventPayload<'typing.start'> => e.type === 'typing.start' guard. Found while migrating the stream-chat-react demo apps to v15 rc (stream-chat 10.0.0-rc.26).

Only typing.start events are ever stored in that slice. The one writer is the typing.start case in Channel._handleChannelEvent (guarded on event.user?.id), typing.stop only removes an entry, and clean() only reads received_at. So the type is narrowed to match what is stored:

• TypingUsersState.typing (and so ChannelStateData['typing']), the channel.state.typing setter and setTypingEvent now use Record<string, EventPayload<'typing.start'>> / EventPayload<'typing.start'>. No new exported alias.
• New compile-time test test/types/typing-state.ts (runs in yarn types and types:dist): Object.values(channel.state.typing)[0].user?.id and .parent_id compile with no guard, the slice type is pinned, and passing a typing.stop to setTypingEvent is rejected. Against the old types it fails with 6 errors.

ai-docs/v10-breaking-changes.md:

• §7 (ChannelState is a StateStore<ChannelStateData>): the parenthetical said stream-chat-react's TypingIndicator "reads the composer copy", which contradicted the same sentence (channel.state is the only owner) and the React v15 guide. It now says the indicator reads channel.state, and documents the narrowed type.
• §18: dropped the "TextComposerState.typing added as required" entry and the typing / setTyping / setTypingEvent / removeTypingEvent members from the TextComposer row of the added-members table. That composer copy was removed in fix: v10 in depth review hotfixes #1920, so both described an API that no longer exists and contradicted §7.

Compatibility: this is narrower than before, so code that assigned non-typing.start events into channel.state.typing or setTypingEvent no longer compiles. Nothing in the SDK does that, and readers only gain.

Test results

• yarn types: pass (includes types:scripts and types:tests)
• yarn lint: clean, zero warnings
• yarn test: 135 files, 4820 tests passed

Changelog

• channel.state.typing and ChannelState.setTypingEvent are typed as typing.start events, so event.user reads without a type guard.

[stream-ci-bot]

🎉 This PR is included in version 10.0.0-rc.27 🎉

The release is available on:

• GitHub release
• npm package (@rc dist-tag)

Your semantic-release bot 📦🚀