Unclear on constants example in the docs

[aidos]

http://martyjs.org/guides/constants/index.html contains the following code snippet regarding the second argument to Constants functions:

var UserActionCreators = Marty.createActionCreators({
  deleteUser: UserConstants.DELETE_USER(function (user) {
    this.dispatch(user);
  }, { foo: true })
});
var FooStore = Marty.createStore({
  handlers: {
    fooAction: { foo: true }
  },
  fooAction: function () {
    ...
  }
})

In the example it looks like by suppling a 2nd arg you're changing the signature used to identify the action in the handler registration later. So you can write { foo: true } instead of UserConstants.DELETE_USER.

Is that what's going on and if so, what's the purpose of it?

[jhollingworth]

Hey, good question. The docs need some improvement here which I will look into. In the meantime:

The second argument is the action creator attributes which you can query using an action predicate. These attributes are useful when you want to listen to actions based on something other than their type e.g. if you wanted to listen to all actions that came from the server, you'd pass in { server: true } as the second argument to the creator and { server: true } as the action predicate.

Does that make sense?

Thanks

[aidos]

Ok, that does make sense. Thanks.

In terms of the rules. What would happen if you queried using more advanced structures? For example, would {server:true, notification:true} pick up events defined as {server:true} as well as {notification:true}?