CODEWITHSUNDEEP
ember.js
Anthony Schwartzman
Anthony Schwartzman

Reputation: 13

Passing controller to this.render in an Ember route renderTemplate hook

This is a question about Ember fundamentals.

Let's consider the following code from the Transitioning to Show Only Incomplete Todos step of the official Ember Getting Started guide.

Todos.TodosActiveRoute = Ember.Route.extend({
  model: function(){
    return this.store.filter('todo', function(todo) {
      return !todo.get('isCompleted');
    });
  },
  renderTemplate: function(controller) {
    this.render('todos/index', {controller: controller});
  }
});

this.render is defining the passed object controller as its controller. This makes sense as far as it goes, but... why?

The application (seems to) work if we call this.render with only the template name argument:

  renderTemplate: function(controller) {
    this.render('todos/index');
  }

The renderTemplate documentation states that it uses the route's controller by default, and that its controller argument is also set to the route's controller. The pattern in the tutorial seems to explicitly declare default behavior. What's going on here?

Upvotes: 1

Views: 716

Answers (1)

Kingpin2k
Kingpin2k

Reputation: 47367

There are three possible causes,

  1. When the guide was written it didn't apply the route's controller when no controller was specified
  2. The person who wrote that guide didn't realize that the route's controller would be applied when one wasn't specified
  3. They wanted to verbosely state they were using the controller for the fun of it

Trek did March 16 2013, https://github.com/emberjs/website/commit/0f2af23799ee2ba3c643303fb96e8b72026f8e7f#diff-750a8e7208fb50dc62974ff56234d69e

And it looks like the functionality was added January 10, 2013 by nragaz https://github.com/emberjs/ember.js/commit/dbe5b4fbcb26fc030cd4fb9fa5ae586217f20a4e

So it looks like I was wrong about #1, and it was probably #2.

Upvotes: 1

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