shopify-liquid

A feature-rich Liquid implementation for Node.js, with compliance with Jekyll and Github Pages. See:

Installation:

npm install --save shopify-liquid

Render from String

Parse and Render:

var Liquid = require('shopify-liquid');
var engine = Liquid();

engine.parseAndRender('{{name | capitalize}}', {name: 'alice'})
    .then(function(html){
        // html === 'Alice'
    });

Caching templates:

var tpl = engine.parse('{{name | capitalize}}');
engine.render(tpl, {name: 'alice'})
    .then(function(html){   
        // html === 'Alice'
    });

Render from File

var engine = Liquid({
    root: path.resolve(__dirname, 'views/'),  // for layouts and includes
    extname: '.liquid',
    cache: false,
    strict_filters: false,       // default: false
    strict_variables: false      // default: false
});
engine.renderFile("hello.liquid", {name: 'alice'})
    .then(function(html){
       // html === 'Alice'
    });
// equivalent to: 
engine.renderFile("hello", {name: 'alice'})
    .then(function(html){
       // html === 'Alice'
    });

root is a directory or an array of directories to resolve layouts and includes, as well as the filename passed in when calling .renderFile(). If an array, the files are looked up in the order they occur in the array. Defaults to process.cwd()
extname is used to lookup the template file when filepath doesn't include an extension name. Defaults to .liquid
cache indicates whether or not to cache resolved templates. Defaults to false.
strict_filters is used to enable strict filter existence. If set to false, undefined filters will be rendered as empty string. Otherwise, undefined filters will cause an exception. Defaults to false.
strict_variables is used to enable strict variable derivation. If set to false, undefined variables will be rendered as empty string. Otherwise, undefined variables will cause an exception. Defaults to false.

Use with Express.js

// register liquid engine
app.engine('liquid', engine.express({
    strict_variables: true,         // Default: fasle
    strict_filters: true            // Default: false
})); 
app.set('views', './views');            // specify the views directory
app.set('view engine', 'liquid');       // set to default

There's an Express demo here.

When using with Express.js, partials(includes and layouts) will be looked up in both Liquid root and Express views directories.

Use in Browser

Download the dist files and import into your HTML. And window.Liquid is what you want. There's also a demo.

<html lang="en">
<head>
  <script src="dist/liquid.min.js"></script>
</head>
<body>
  <script>
    var engine = window.Liquid();
    var src = '{{ name | capitalize}}';
    var ctx = {
      name: 'welcome to Shopify Liquid'
    };
    engine.parseAndRender(src, ctx)
      .then(function(html) {
        // html === Welcome to Shopify Liquid 
      });
  </script>
</body>
</html>

Note: any-promise browser requires a polyfill or explicit registration. e.g: require('any-promise/register/bluebird')

Includes

// file: color.liquid
color: '{{ color }}' shape: '{{ shape }}'

// file: theme.liquid
{% assign shape = 'circle' %}
{% include 'color' %}
{% include 'color' with 'red' %}
{% include 'color', color: 'yellow', shape: 'square' %}

The output will be:

color: '' shape: 'circle'
color: 'red' shape: 'circle'
color: 'yellow' shape: 'square'

Layouts

// file: default-layout.liquid
Header
{% block content %}My default content{% endblock %}
Footer

// file: page.liquid
{% layout "default-layout" %}
{% block content %}My page content{% endblock %}

The output of page.liquid:

Header
My page content
Footer

It's possible to define multiple blocks.
block name is optional when there's only one block.

Register Filters

// Usage: {{ name | uppper }}
engine.registerFilter('upper', function(v){
    return v.toUpperCase();
});

See existing filter implementations: https://github.com/harttle/shopify-liquid/blob/master/filters.js

Register Tags

// Usage: {% upper name%}
engine.registerTag('upper', {
    parse: function(tagToken, remainTokens) {
        this.str = tagToken.args; // name
    },
    render: function(scope, hash) {
        var str = Liquid.evalValue(this.str, scope); // 'alice'
        return Promise.resolve(str.toUpperCase()); // 'Alice'
    }
});

See existing tag implementations: https://github.com/harttle/shopify-liquid/blob/master/tags/

Contribution Guide

Make a fork.
Write a test to demonstrate your feature is not supported yet.
Optionaly, change source files to make all test pass.
Create a pull request.