Use string literal type for action type

[OliverJAsh]

No description provided.

[supasate]

Why do we need to change this? How does it affect the result?

[OliverJAsh]

This is needed for TypeScript's control flow analysis, e.g.:

const reducer = (state, action: LocationChangeAction | MyOtherAction) => {
  switch (action.type) {
    case LOCATION_CHANGE: {
      // Here, TypeScript knows `action` is type `LocationChangeAction`, and has a property called `payload`, which has a property called `location`
    }
  }
}

If the action type was not a string literal, TypeScript's control flow analysis wouldn't be able to narrow the union.