Development Helpers
Handlebars and Ember come with a few helpers that can make developing your templates a bit easier. These helpers make it simple to output variables into your browser's console, or activate the debugger from your templates.
Logging
The {{log}} helper makes it easy to output variables or expressions in
the
current rendering context into your browser's console:
{{log 'Name is:' name}}
The {{log}} helper also accepts primitive types such as strings or numbers.
Adding a breakpoint
The {{debugger}} helper provides a handlebars equivalent to JavaScript's
debugger keyword. It will halt execution inside the debugger helper and give
you the ability to inspect the current rendering context:
{{debugger}}
When using the debugger helper you will have access to a get function. This
function retrieves values available in the context of the template.
For example, if you're wondering why a value {{foo}} isn't rendering as
expected within a template, you could place a {{debugger}} statement and,
when the debugger; breakpoint is hit, you can attempt to retrieve this value:
> get('foo')
get is also aware of keywords. So in this situation:
{{#each items as |item|}}
{{debugger}}
{{/each}}
You'll be able to get values from the current item:
> get('item.name')
You can also access the context of the view to make sure it is the object that you expect:
> context