# Template engines

By default, Fractal uses Handlebars to render view templates for both components and documentation pages. It's bundled with a number of built-in Fractal helpers, but you can also customise it to include your own custom helpers and/or partials if required.

However, it's easy to use an alternate template engine (via the use of adapters) if you need a more bespoke solution for your project.

# Customising Handlebars

See the view templates documentation for details on how to customise the default Handlebars install to include your own helpers or partials.

# Loading template engines

Template engines for components and documentation pages are loaded separately, using the fractal.components.engine() and fractal.docs.engine() methods respectively.

If you don't need to customise the template engine adapter, you can just pass its package name into the .engine() method directly:

fractal.components.engine('@frctl/nunjucks'); // use Nunjucks for components
fractal.docs.engine('@frctl/mustache'); // use Mustache for docs

You will also likely want to change the file extension for the view template using the ext configuration option:

fractal.components.set('ext', '.nunj');
fractal.docs.set('ext', '.html');


You must install your chosen template adapter package via npm install before you can use it with Fractal.

# Customising adapters

If you wish to first customise the behaviour of the adapter (for instance to add helper methods or suchlike), the .engine() method will also accept a configured template engine adapter instance.

The following is an example using the Fractal Nunjucks adapter (opens new window):

const nunjucks = require('@frctl/nunjucks')({
    filters: {
        shorten: function(str, count) {
            return str.slice(0, count || 5); // bespoke 'shorten' filter to use in view templates
    // ...other config properties here

fractal.components.engine(nunjucks); // use the configured Nunjucks instance for components
fractal.components.set('ext', '.nunj'); // look for files with a .nunj file extension


Configuration details can vary between adapters, so you should refer to your chosen adapter's documentation for full configuration and setup details.

# Available adapters

Currently there are specific 'official' adapters implemented for Handlebars, Mustache (opens new window), Nunjucks (opens new window) and Twig (opens new window). However, if you want to use something else, there is also a generic adapter (opens new window) that uses the Consolidate.js library to provide compatibility with 30+ other template engines.

For full information on installing, using and customising individual template engine adapters, see the appropriate READMEs: