liquidjs
This is a liquid implementation for both Node.js and browsers. Website: http://harttle.github.io/liquidjs/, Live Demo: https://jsfiddle.net/6u40xbzs/
Features
- Fully compatible to shopify, with all tags and filters implemented
- Support layout(extend) and include syntax
- In pure JavaScript with Promise-based API
Differences
Though being compatible with Ruby Liquid is one of our priorities, there're still certain differences. You may need some configuration to get it compatible in these senarios:
- Dynamic file locating (enabled by default), which means layout/partial name can be an variable in liquidjs. See #51.
- Truthy and Falsy. All values except undefined,null,falseare truthy, whereas in Ruby Liquid all exceptnilandfalseare truthy. See #26.
- Number Rendering. Since JavaScript do not distinguish floatandinteger, we cannot either convert between them nor render regarding to their type. See #59.
- .to_liquid() has a .toLiquid()alias and and the JavaScript.toString()is aliased to.to_s().
- .to_s() uses JSON.prototype.stringifyas default, rather than Ruby's inspect.
TOC
- Usage
- API Spec
- Contribute Guidelines
Render from String
Install as Node.js dependency:
# You'll need a promise-polyfill for Node.js < 4
npm install --save liquidjs
Parse and Render:
var Liquid = require('liquidjs');
var engine = Liquid();
engine
    .parseAndRender('{{name | capitalize}}', {name: 'alice'})
    .then(console.log);
// outputs 'Alice'
Caching templates:
var tpl = engine.parse('{{name | capitalize}}');
engine
    .render(tpl, {name: 'alice'})
    .then(console.log);
// outputs 'Alice'
Render from File
var engine = Liquid({
    root: path.resolve(__dirname, 'views/'),  // dirs to lookup layouts/includes
    extname: '.liquid'          // the extname used for layouts/includes, defaults ""
});
engine.renderFile("hello.liquid", {name: 'alice'})
    .then(console.log)  // outputs "Alice"
// which is equivalent to: 
engine
    .renderFile("hello", {name: 'alice'})
    .then(console.log)  // outputs "Alice"
Use with Express.js
// register liquid engine
app.engine('liquid', engine.express()); 
app.set('views', './views');            // specify the views directory
app.set('view engine', 'liquid');       // set to default
Here's an Express demo. When used with Express.js,
Express views will be included when looking up
partials(includes and layouts).
Use in Browser
You can get a dist file for browsers from
- Releases page for liquidjs, or
- unpkg.com: https://unpkg.com/liquidjs/dist/liquid.min.js
Here's the demo:
- JSFiddle: https://jsfiddle.net/6u40xbzs/
- Demo directory: /demo/browser/.
Note: For IE and Android UC browser, you will need a Promise polyfill.
Include Partials
// 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'
Layout Templates (Extends)
// 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.
Options
The full list of options for Liquid() is listed as following:
- 
rootis 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["."]
- 
extnameis used to lookup the template file when filepath doesn't include an extension name. Eg: setting to".html"will allow including file by basename. Defaults to"".
- 
cacheindicates whether or not to cache resolved templates. Defaults tofalse.
- 
dynamicPartials: if set, treat<filepath>parameter in{%include filepath %},{%layout filepath%}as a variable, otherwise as a literal value. Defaults totrue.
- 
strict_filtersis used to enable strict filter existence. If set tofalse, undefined filters will be rendered as empty string. Otherwise, undefined filters will cause an exception. Defaults tofalse.
- 
strict_variablesis used to enable strict variable derivation. If set tofalse, undefined variables will be rendered as empty string. Otherwise, undefined variables will cause an exception. Defaults tofalse.
- 
trim_tag_rightis used to strip blank characters (including\t, and\r) from the right of tags ({% %}) until\n(inclusive). Defaults tofalse.
- 
trim_tag_leftis similiar totrim_tag_right, whereas the\nis exclusive. Defaults tofalse. See Whitespace Control for details.
- 
trim_value_rightis used to strip blank characters (including\t, and\r) from the right of values ({{ }}) until\n(inclusive). Defaults tofalse.
- 
trim_value_leftis similiar totrim_value_right, whereas the\nis exclusive. Defaults tofalse. See Whitespace Control for details.
- 
greedyis used to specify whethertrim_left/trim_rightis greedy. When set totrue, all consecutive blank characters including\nwill be trimed regardless of line breaks. Defaults totrue.
Register Filters
// Usage: {{ name | uppper }}
engine.registerFilter('upper', v => v.toUpperCase())
Filter arguments will be passed to the registered filter function, for example:
// Usage: {{ 1 | add: 2, 3 }}
engine.registerFilter('add', (initial, arg1, arg2) => initial + arg1 + arg2)
See existing filter implementations here: https://github.com/harttle/liquidjs/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'
    }
});
- parse: Read tokens from- remainTokensuntil your end token.
- render: Combine scope data with your parsed tokens into HTML string.
See existing tag implementations here: https://github.com/harttle/liquidjs/blob/master/tags/
Plugin API
A pack of tags or filters can be encapsulated into a plugin, which will be typically installed via npm.
engine.plugin(require('./some-plugin'));
// some-plugin.js
module.exports = function (Liquid) {
    // here `this` refers to the engine instance
    // `Liquid` provides facilities to implement tags and filters
    this.registerFilter('foo', x => x);
}
Plugin List:
- To add your plugin, contact me or simply send a PR.
Contribute Guidelines
This repo uses eslint to check code style, semantic-release to generate changelog and publish to npm and Github Releases.
- Code Style: https://github.com/standard/eslint-config-standard, npm run lintto check locally.
- Commit Message: https://github.com/angular/angular.js/blob/master/DEVELOPERS.md#commits
