Typing of createAction with accessing event properties

[alexamy]

What is a way to properly type events when using createAction?

CodeSandbox, TypeScript error on line 18:

Property 'text' does not exist on type '{ type: "started"; } | { type: "updated"; text: string; }'.
  Property 'text' does not exist on type '{ type: "started"; }'.typescript(2339)

One possible way is assertEvent, but it would be more suitable to use TypeScript, if possible.

[davidkpiano]

assertEvent is most suitable here because this action can be called with any event.

If it cannot be, it may be better to define it inline.