Typescript conditional types provide a new approach to proper typing of Redux actions and action-factories.
Countless blogs and libraries have been written on this subject, trying to work around the limitations of the default type definitions of Redux. However, these numerous attempts to reduce boilerplate and to improve type cohesion unfortunately remained unsatisfactory without conditional types.
Working through our (enormous) backlog of unsorted TypeScript "Suggestions" and it's remarkable how many of them are solved by conditional types.