Emberjs Handlebars precompiling

Stargazer picture Stargazer · Mar 25, 2012 · Viewed 19.2k times · Source

My Emberjs app is running slowly so I wanted to precompile my template to ease the runtime a bit. However I'm lost on how to proceed. I read http://handlebarsjs.com/precompilation.html and Emberjs introduction but no, all I could do was just creating a template file as instructed on the site, and I cannot figure out what and how to do with this template file in Emberjs.

How can I precompile templates in Emberjs? What should I do with the template file to use it in Emberjs?

Answer

Gabriel Grant picture Gabriel Grant · Sep 15, 2012

To clarify, Thomas' example as-written is still doing the template compilation at run-time. I think his point, though, was that after you've loaded your precompiled Ember-Handlebars templates you can do this:

MyApp.MyView = Ember.View.extend({
  template: Ember.TEMPLATES.mytemplate,
})

The problem with using Handlebars' built-in precompiler is that Ember's Handlebars implementation adds some functionality on top of what Handlebars itself provides, so you'll want to install the ember-precompile package, which provides basically the same interface as the handlebars command-line utility, but using Ember's Handlebars implementation.

This will avoid you having to change all your templateNames to templates and having to add in the Ember.TEMPLATES... in each view, since it automatically updates Ember's built-in template cache.

So, assuming you've already loaded your pre-complied templates.js file as output from ember-precompile templates/*.handlebars -f templates/templates.js, here's a more complete example snippet of a worker import/initialization order:

<script src="/lib/handlebars-1.0.0.beta.6.js"></script>
<script src="/lib/ember-1.0.pre.js"></script>
<script src="/lib/ember-data-latest.js"></script>
<script>
  var App = Ember.Application.create();
</script>
<script src="/templates/templates.js"></script>
<script src="/js/models.js"></script>
<script src="/js/views.js"></script>
<script src="/js/controllers.js"></script>
<script src="/js/router.js"></script>
<script>
  App.initialize();
</script>