The normal advice is that `actionType` should be a string. This is purely for debugging purposes. If the tools used for debugging are altered, then it would be easier to use something other than a string.
Using a function means you don't have to have a separate action variable from the action creator itself:
```js
some someActionCreator = () => ({
type: someActionCreator,
})
```
Redux doesn't care if your action type is a string, object, symbol or whatever. Even @gaearon noted it should be a Symbol for uniqueness, but only said to use strings because of the debugging potential.
Another benefit of using functions is you're only comparing memory references rather than strings. This is a performance boost, but probably not one that will manifest in most applications.
We could even take this further to include `symbol.description` and `classInstance.constructor.name`.
The one downfall is most Redux tooling both utilizes and expects strings. This would need to change. Even `createReducer` would need to take a `Map` of actions instead of an `Object` or this wouldn't work.
