v5.0.0-beta.0

[markerikson]

This beta release alters our TS types to add and use a new UnknownAction type where possible for better type safety, and includes all prior changes from the 5.0 alphas. This release has breaking changes from 4.x.

We recommend that users should prefer using Redux Toolkit for Redux development, and use the RTK 2.0 beta that depends on this core release, rather than using the Redux core library directly

npm i redux@next

yarn add redux@next

Changelog

New UnknownAction Type

The Redux TS types have always exported an AnyAction type, which is defined to have {type: string} and treat any other field as any. This makes it easy to write uses like console.log(action.whatever), but unfortunately does not provide any meaningful type safety.

We now export an UnknownAction type, which treats all fields other than action.type as unknown. This encourages users to write type guards that check the action object and assert its specific TS type. Inside of those checks, you can access a field with better type safety.

UnknownAction is now the default any place in the Redux source that expects an action object.

AnyAction still exists for compatibility, but has been marked as deprecated.

Note that Redux Toolkit's action creators have a .match() method that acts as a useful type guard:

if (todoAdded.match(someUnknownAction)) {
  // action is now typed as a PayloadAction<Todo>
}

Earlier Alpha Changes

Summarizing changes from the earlier 5.0-alpha releases:

• Source code converted to TS
• createStore deprecation tag ported
• Removed isMinified check
• Packaging converted to have full ESM/CJS compatibility
• Dropped UMD build artifacts
• JS build output is now "modern" and not transpiled for IE11 compatibility
• Listener subscriptions are now a Set
• Store enhancer types improved
• Reducer type accepts a PreloadedState generic
• Middleware action and next are typed as unknown
• action.type field must be a string

What's Changed

• Prefer use of Action or UnknownAction instead of AnyAction by @EskiMojo14 in Prefer use of Action or UnknownAction instead of AnyAction #4520

Full Changelog: v5.0.0-alpha.6...v5.0.0-beta.0

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This discussion was created from the release v5.0.0-beta.0.