Ember.js code that *will* cause performance problems

index.md

ember-views/view.js

Your element won't render until the next frame. This will cause a flash.

// Schedule the DOM element to be created and appended to the given
// element after bindings have synchronized.
this._insertElementLater(function() {
  this.$().appendTo(target);
});

Other performance problems

• http://stackoverflow.com/questions/10358065/animated-gif-pauses-when-ember-js-objects-are-loading
• You need to start building full-on UI components (https://github.com/flamejs/flame.js/tree/master/views), so you need to start having a TON more javascript on the client.
• when view.set('isVisible', false), the bindings are still going to execute
• http://jsfiddle.net/viatropos/PSkqS/3/

White flashes

• when an Ember.CollectionView goes from full to empty and back and forth, it flashes. Is this because it's taking 2 frames?

Questions

• what happens when you remove vs. destroy a view, are the bindings removed? are the bindings still executing?
• how do you specify default values for a computed property?

Performance Optimizations

• use detach in addition to remove, so you can keep the cached element if you are going to redraw it (http://api.jquery.com/detach/)
• somehow make bindings stop working until an object is set from isVisible: false to isVisible: true