Extend the view or use mixin in Ember.js

Question

I would like to include standard functionality in several views in an Ember application. Functionality includes such things as setting the tagName and classNames in the views the same and tracking properties for each view.

Question in a nutshell: should you use mixing or expand the base view?

Extended question ...

Is it possible to expand the base view to do this? For instance:

App.BaseView = Em.View.extend({ tagName: 'section', classNames: ['page_section', 'blue'], willInsertElement: function() { // Some functions called here that set properties }, }); App.PageOneView = App.BaseView.extend({ // View specific stuff here }); App.PageTwoView = App.BaseView.extend({ // View specific stuff here }); 

... Or should you use Mixin to extend functionality? For instance:

 App.BaseMixin = Em.Mixin.create({ tagName: 'section', classNames: ['page_section', 'blue'], willInsertElement: function() { // Some functions called here that set properties }, }); App.PageOneView = Em.View.extend(App.BaseMixin, { // View specific stuff here }); App.PageTwoView = Em.View.extend(App.BaseMixin, { // View specific stuff here }); 

I understand that views and mixins are both Ember objects, but whether they use either of them to extend standard functions to other objects (e.g., views) affects the way objects and prototypes / instances interact (if they differ from the object) , and properties are set in the instance of the view or view object?

If the two examples above are different, will the properties in the mixin initialization function change anything? For instance:

 App.BaseMixin = Em.Mixin.create({ tagName: null, classNames: null, init: function() { this.set('tagName', 'section'); // And so forth... }, }); 

However, if the use of mixin and the extension of the view have the same effect on the views to which I am trying to add standard functionality (that is, they equally affect the view objects and prototypes / instances), do you see the advantage of using one over the other (whether with point of view of efficiency, maintainability, etc.)?

Answer 1

Great question,

Short and simple, increase the presentation.

• Hooks / bindings are view-specific, so mixin cannot be applied to a controller, route, etc., and depending on the composition of your team, you do not want to give anyone the opportunity to mix code that does not belong.

• Extending a class in Ember simply turns the base class into a mixin and applies it to your class. https://github.com/emberjs/ember.js/blob/v1.2.0/packages/ember-runtime/lib/system/core_object.js#L488

So this is almost the same, only your base view makes more sense, since it really only applies to views.