Functional Templates are Handlebars Helpers or EmberJs Components which do not render any output. They perform simple and independent side-tasks, i.e. they change the variables of the current scope of your template. At first it does not sound useful at all, but consider simple constructs like if-then-else or for-each – widely accepted and known to be very useful indeed.

1. Functional Templates
EmberJs und Handlebars

2. Christoph Dähne
christoph.daehne@sandstorm.de
www.sandstorm.de

3. {{x-sort-by list=friends property="name" as |sorted|}}
{{#each sorted as |friend|}}
…
{{/each}}
{{/x-sort-by}}

4. {{x-map-to-list list=friendsByName as |friends|}}
…
{{/x-map-to-list}}

5. {{findAll persons field="isFriend" assignTo="friends"}}
{{#sort friends sortBy="name" assignTo="sorted"}}
{{#each sorted}}
…
{{/each}}
{{/sort}}
{{/findAll}}

6. Source Codes and More Details
https://sandstorm.de/de/blog/functional-templates-in-
handlebars.html
Inspiring Blog Article
http://frontside.io/blog/2016/01/22/functional-templating-in-
ember.html