# shopify-liquid
[](https://www.npmjs.org/package/shopify-liquid)
[](https://travis-ci.org/harttle/shopify-liquid)
[](https://coveralls.io/github/harttle/shopify-liquid?branch=master)
[](https://github.com/harttle/shopify-liquid/issues)
A Liquid template engine with a wide range of tags and filters,
for both Node.js and browsers.
Here's a live demo:
> The Liquid template engine is implemented in Ruby originally,
> which is used by [Jekyll][jekyll] and [Github Pages][gh].
Features:
* A wide range of [filters](https://github.com/harttle/shopify-liquid/wiki/Builtin-Filters) and [tags](https://github.com/harttle/shopify-liquid/wiki/Builtin-Tags)
* Easy tag/filter registration, allows async tags
* [any-promise][any-promise]
Installation:
```bash
npm install --save shopify-liquid
```
## Render from String
Parse and Render:
```javascript
var Liquid = require('shopify-liquid');
var engine = Liquid();
engine.parseAndRender('{{name | capitalize}}', {name: 'alice'})
.then(function(html){
// html === 'Alice'
});
```
Caching templates:
```javascript
var tpl = engine.parse('{{name | capitalize}}');
engine.render(tpl, {name: 'alice'})
.then(function(html){
// html === 'Alice'
});
```
## Render from File
```javascript
var engine = Liquid({
root: path.resolve(__dirname, 'views/'), // dirs to lookup layouts/includes
extname: '.liquid' // the default extname used for layouts/includes
});
engine.renderFile("hello.liquid", {name: 'alice'})
.then(function(html){
// html === 'Alice'
});
// equivalent to:
engine.renderFile("hello", {name: 'alice'})
.then(function(html){
// html === 'Alice'
});
```
## Options
The full list of options for `Liquid()` is listed as following:
* `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 `["."]`
* `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`.
* `trim_right` is used to strip blank characters (including ` `, `\t`, and `\r`) from the right of tags (`{% %}`) until `\n` (inclusive). Defaults to `false`.
* `trim_left` is similiar to `trim_right`, whereas the `\n` is exclusive. Defaults to `false`. See [Whitespace Control][whitespace control] for details.
* `greedy` is used to specify whether `trim_left`/`trim_right` is greedy. When set to `true`, all successive blank characters including `\n` will be trimed regardless of line breaks. Defaults to `false`.
## Use with Express.js
```javascript
// register liquid engine
app.engine('liquid', engine.express());
app.set('views', './views'); // specify the views directory
app.set('view engine', 'liquid'); // set to default
```
> There's an Express demo [here](demo/express/).
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][releases] the dist files and import into your HTML.
And `window.Liquid` is what you want. There's also a [demo](demo/browser/).
```html
```
Note: In [IE and Android UC][caniuse-promises] browser, you need a Promise implementation
registered to [any-promise][any-promise].
## 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
```javascript
// Usage: {{ name | uppper }}
engine.registerFilter('upper', function(v){
return v.toUpperCase();
});
```
> See existing filter implementations:
## Register Tags
```javascript
// 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:
## Contribution Guide
1. Write a [test][test] to define the feature you want.
2. File an issue, or optionally:
3. Get your test pass and make a pull request.
[nunjucks]: http://mozilla.github.io/nunjucks/
[liquid-node]: https://github.com/sirlantis/liquid-node
[shopify-liquid]: https://shopify.github.io/liquid/
[jekyll]: http://jekyllrb.com/
[gh]: https://pages.github.com/
[releases]: https://github.com/harttle/shopify-liquid/releases
[any-promise]: https://github.com/kevinbeaty/any-promise
[test]: https://github.com/harttle/shopify-liquid/tree/master/test
[caniuse-promises]: http://caniuse.com/#feat=promises
[whitespace control]: https://github.com/harttle/shopify-liquid/wiki/Whitespace-Control