raphaelcosta / handlebars.rb

Ruby Bindings for Handlebars.js

Handlebars.rb

This uses therubyracer to bind to the actual JavaScript implementation of Handlebars.js so that you can use it from ruby.

Usage

Simple stuff

require 'handlebars'
handlebars = Handlebars::Context.new
template = handlebars.compile("{{say}} {{what}}")
template.call(:say => "Hey", :what => "Yuh!") #=> "Hey Yuh!"

functions as properties

template.call(:say => "Hey ", :what => lambda {|this| ("yo" * 2) + "!"}) #=> "Hey yoyo!"

Block Helpers:

Just like JavaScript, you can write block helpers with an {{else}} section. To print out a section twice if a condition is met:

handlebars.register_helper(:twice) do |context, condition, block|
  if condition
    "#{block.fn(context)}#{block.fn(context)}"
  else
    block.inverse(context)
  end
end
template = handlebars.compile("{{#twice foo}}Hurray!{{else}}Boo!{{/twice}}")
template.call(foo: true) #=> Hurray!Hurray!
template.call(foo: false) #=> Boo!

Safe Strings

By default, handlebars will escape strings that are returned by your block helpers. To mark a string as safe:

template = handlebars.compile("{{safe}}")
template.call(:safe => proc {Handlebars::SafeString.new("<pre>Totally Safe!<pre>")})

Partials

You can directly register partials

handlebars.register_partial("whoami", "I am {{who}}")
handlebars.compile("{{>whoami}}").call(:who => 'Legend') #=> I am Legend

Partials can also be dynamically looked up by defining a partial_missing behavior:

handlebars.partial_missing do |name|
  "unable to find >#{name}"
end
handlebars.compile("{{>missing}}").call #=> unable to find >missing

Missing partials can also be returned as a function:

count = 0
handlebars.partial_missing do |name|
  lambda do |this, context, options|
    count += 1
    "#{count} miss(es) when trying to look up a partial"
  end
end
t = handlebars.compile("{{>missing}}")
t.call #=> 1 miss(es) when trying to look up a partial
t.call #=> 2 miss(es) when tyring to look up a partial

Test

rspec spec/