Add View Constructor events

[jasonLaster]

Disclaimer, I'm not sure if this is a great idea, but it is really powerful and helps a use case I'm currently running into.

 Marionette.View = Backbone.View.extend({
   constructor: function(options) {
+    this.triggerMethod('before:constructor', options);
     _.bindAll(this, 'render');

     Backbone.View.apply(this, arguments);
     Marionette.MonitorDOMRefresh(this);
     this.listenTo(this, 'show', this.onShowCalled);
+    this.triggerMethod('constructor', options);
   },
 });

---

The problem that I have is that I'd like all of my views to have a viewName which is added to the view's el attribute hash.

I want this API:

ItemView.extend({
  viewName: 'my-view'
})

<div data-view-name="my-view"></div>

I want to turn viewName into attributes.data-view-name, which is really easy with onBeforeConstructor

ItemView.extend({
  attribues: {
    data-view-name: 'my-view'
  } 
})

_.extend(View.prototype, {
   onBeforeConstructor: function() {
     if (this.viewName) {
       this.attributes['data-view-name'] = this.viewName
     }
  }
});

[jamesplease]

I've thought about this feautre, too. It would be a nice complement to the destroy event. WIth that said, I can see it being initialize instead of constructor, so that the name is a verb like all the other events.

For our lifecycle objects this would give us a nice set of lifecycle events:

start/stop initialize/destroy

Also, I'd want this on every Marionette Class...not just Views.

[jasonLaster]

yea, before:initialize would be rocking

[Anachron]

:+1: for all Marionette classes having this event.

[jasonLaster]

Yup, I think before:initialize would be rad. Would add it to Object, Module, etc...

[jamiebuilds]

Wouldn't before:initialize imply:

constructor: function() {
  // constructor stuf...
  this.triggerMethod('before:initialize');
  this.initialize.apply(this, arguments);
  this.triggerMethod('initialize');
}
// vs.
constructor: function() {
  this.triggerMethod('before:constructor');  
  // constructor stuf...
  this.initialize.apply(this, arguments);
  this.triggerMethod('constructor');
}

[jamesplease]

Good thought, @thejameskyle. That's possible. We should definitely go with a verb, so constructor just won't do. Perhaps before:instantiate is better?

[jamiebuilds]

I think instantiate sounds/reads too much like initialize.

Other verbs: construct, create

[jamesplease]

We might need to re-think our inheritance if we add this.

LayoutView calls ItemView's initialize, which calls View's initialize, so there's no clear way to make a before initialize that functions the same across all of the Classes.

If we include it in all 3, it'll be called three times. If it's in View, it'll be called in the middle of initialization, and if it's in anything else then the 'parent' Classes will miss out on the event.

I think instantiate sounds/reads too much like initialize.

Other verbs: construct, create

Mmm...I'm not sure if I think the two words being similar is an issue.

[jamiebuilds]

Mmm...I'm not sure if I think the two words being similar is an issue.

I would confuse the two every single time it came up

[jasonLaster]

hmm, maybe to be consistent with initialize we add preInitialize as a noop function to View.prototype and call it at the beginning of the constructor. That way, preInitialize and initialize are consistent sibling hooks.

If we use triggerMethod, I'd vote for triggerMethod('construct')

[samccone]

preInitialize* :)

[samccone]

but what about prepreinitialize

[jamiebuilds]

preInitialize... has science gone too far?

[Anachron]

Random stuff: beforeAssamble, beforeConstruct, beforeOriginate.

[jamesplease]

Appending pre makes no sense...every other event uses before:.

before:someVerb

^ consistency

[jamiebuilds]

Going back to the original reasoning for this. Is there not a better way to do it?

[jamiebuilds]

Ping @marionettejs/marionette-core. This issue has not been resolved for a long time.

[samccone]

i am cool with before:initialize and initialize

[jamesplease]

I think the problem here is the potential infeasability of the feature. How can we prevent multiple before:initializes with constructor inheritance?

[samccone]

I would assume we would only add it to marionette.view and marionette.object (and controller for now).

[jasonLaster]

Going to second what @samccone said. We'd add it to Marionette.View and all other Marionette classes like Object, Controller, etc...

[jamesplease]

Ehhh..I don't think I like that. For LayoutView, the order would be:

layoutView constructor
itemView constructor
before:initialize
view constructor
initialize

This seems really, really terrible to me. How could we even document this behavior in a way that makes it easy to understand?

before:initialize is called before the constructor method. But not all of the constructor methods. Just the Marionette.View's constructor. So crack open the source and figure out what each constructor does, just so you make sure you know when exactly the event is triggered.

[jamiebuilds]

Following what @jmeas said I'm :-1: to this idea.

[jamesplease]

A crazy idea I've been thinking about for some time might let us support this as our users intend it to work. Once I work it out more I'll write up the details

nvm.

[samccone]

:lock:

[jasonLaster]

hmm. interesting - will close the issue, but warning I might come back to this later.

I think there's a lot to be said for adding a hook for advanced users and we did just get rid of absolute constructor references.