Improve defining action types

[jhollingworth]

Our current approach to defining action types has a number of drawbacks:

1. We can't support ES6 function declarations (e.g. { foo() { })
2. Feedback I've had is that invokable constants is a little odd (I agree)
3. Action creators become really long (e.g. updateCriteria: SomeConstants.UPDATE_CRITERIA(function (profileId, criteria) { ...)
4. We mess with function contexts

Function annotations solve this problem perfectly. Unfortunately it won't be in any spec anytime soon. So we need an alternative approach.

The two contenders right now:

Have a type hash

• Pros
  • Simple, easy to understand, terse
  • Precedent: We already do this with stores
• Cons
  • Action type is not co-located with action function
  • Cannot support properties
  • Messing with context

var UserActionCreators = Marty.createActionCreators({
  types: {
    addUser: Constants.ADD_USER
  },
  addUser: function(user) {
    var user = UserUtils.createUser(name);
    this.dispatch(user);
    return UserHttpAPI.createUser(user);
  }
})

Invoke constant inside of creator

• Pros
  • Don't mess with context
  • Don't have to proxy action creator functions
  • Can have multiple action types to a function
• Cons
  • More complicated, need understand JS well to use this
  • 1 extra line of code
  • Cannot enforce everything has an action type

var UserActionCreators = Marty.createActionCreators({
  addUser: function(name) {
    return Constants.ADD_USER(function(dispatch) {
      var user = UserUtils.createUser(name);
      dispatch(user);
      return UserHttpAPI.createUser(user);
    }, this);
  }
})

[therealcisse]

Invoke constant inside of creator.

+1

The intent of dispatch is really clear here and:

Can have multiple action types to a function.

This could be a cool feature.

[oliverwoodings]

I prefer option 1, mainly because you can then do cool stuff like this:

var UserActionCreators = new ActionCreators({
  types: {
    addUser: Constants.ADD_USER
  }
});

And have Marty automatically create the addUser method for you (with it auto dispatching). I think it also looks much cleaner and will be easier for people to understand. Trying to get across that 'you have to return an instance of a constant' is not going to be easy.

[jhollingworth]

In Marty v0.9