mustache.js — Logic-less templates with JavaScript

What could be more logical awesome than no logic at all?

For a list of implementations (other than JavaScript) and editor plugins, see http://mustache.github.com/.

Where to Use?

You can use mustache.js rendering stuff in various scenarios. E.g. you can render templates in your browser, or rendering server-side stuff with node.js, use it for rendering stuff in CouchDB's views.

Who Uses Mustache?

An updated list is kept on the Github wiki. Add yourself, if you use mustache.js: http://wiki.github.com/janl/mustache.js/beard-competition

Usage

A quick example how to use mustache.js:

var view = {
  title: "Joe",
  calc: function() {
    return 2 + 4;
  }
}

var template = "{{title}} spends {{calc}}";

var html = Mustache.to_html(template, view);

template is a simple string with mustache tags and view is a JavaScript object containing the.

Template Tag Types

There are several types of tags currently implemented in mustache.js.

For a language-agnostic overview of Mustache's template syntax, see the mustache(5) manpage or http://mustache.github.com/mustache.5.html.

Simple Tags

Tags are always surrounded by mustaches like this {{foobar}}.

var view = {name: "Joe", say_hello: function(){ return "hello" }}

template = "{{say_hello}}, {{name}}"

Conditional Sections

Conditional sections begin with {{#condition}} and end with {{/condition}}. When condition evaluates to true, the section is rendered, otherwise the hole block will output nothing at all. condition may be a function returning true/false or a simple boolean.

var view = {condition: function() {
  // [...your code goes here...]
  return true;
}}

{{#condition}}
  I will be visible if condition is true
{{/condition}}

Enumerable Sections

Enumerable Sections use the same syntax as condition sections do. {{#shopping_items}} and {{/shopping_items}}. Actually the view decides how mustache.js renders the section. If the view returns an array, it will iterator over the items. Use {{.}} to access the current item inside the enumeration section.

var view = {name: "Joe's shopping card",
            items: ["bananas", "apples"]}

var template = "{{name}}: <ul> {{#items}}<li>{{.}}</li>{{/items}} </ul>"

Outputs:
Joe's shopping card: <ul><li>bananas</li><li>apples</li></ul>

Higher Order Sections

If a section key returns a function, it will be called and passed both the unrendered block of text and a renderer convenience function.

Given this JS:

"name": "Tater",
"bolder": function() {
  return function(text, render) {
    return "<b>" + render(text) + '</b>'
  }
}

And this template:

{{#bolder}}Hi {{name}}.{{/bolder}}

We'll get this output:

<b>Hi Tater.</b>

As you can see, we're pre-processing the text in the block. This can be used to implement caching, filters (like syntax highlighting), etc.

You can use this.name to access the attribute name from your view.

Dereferencing Section

If you have a nested object structure in your view, it can sometimes be easier to use sections like this:

var objects = {
  a_object: {
    title: 'this is an object',
    description: 'one of its attributes is a list',
    a_list: [{label: 'listitem1'}, {label: 'listitem2'}]
  }
};

This is our template:

{{#a_object}}
  <h1>{{title}}</h1>
  <p>{{description}}</p>
  <ul>
    {{#a_list}}
      <li>{{label}}</li>
    {{/a_list}}
  </ul>
{{/a_object}}

Here is the result:

<h1>this is an object</h1>
  <p>one of its attributes is a list</p>
  <ul>
    <li>listitem1</li>
    <li>listitem2</li>
  </ul>

View Partials

mustache.js supports a quite powerful but yet simple view partial mechanism. Use the following syntax for partials: {{>partial_name}}

var view = {
  name: "Joe",
  winnings: {
    value: 1000,
    taxed_value: function() {
        return this.value - (this.value * 0.4);
    }
  }
};

var template = "Welcome, {{name}}! {{>winnings}}"
var partials = {
  winnings: "You just won ${{value}} (which is ${{taxed_value}} after tax)"};

var output = Mustache.to_html(template, view, partials)

output will be:
Welcome, Joe! You just won $1000 (which is $600 after tax)

You invoke a partial with {{>winnings}}. Invoking the partial winnings will tell mustache.js to look for a object in the context's property winnings. It will then use that object as the context for the template found in partials for winnings.

Escaping

mustache.js does escape all values when using the standard double mustache syntax. Characters which will be escaped: & \ " < >. To disable escaping, simply use tripple mustaches like {{{unescaped_variable}}}.

Example: Using {{variable}} inside a template for 5 > 2 will result in 5 > 2, where as the usage of {{{variable}}} will result in 5 > 2.

Streaming

To stream template results out of mustache.js, you can pass an optional send() callback to the to_html() call:

Mustache.to_html(template, view, partials, function(line) {
  print(line);
});

Pragmas

Pragma tags let you alter the behaviour of mustache.js. They have the format of

{{%PRAGMANAME}}

and they accept options:

{{%PRAGMANAME option=value}}

IMPLICIT-ITERATOR

When using a block to iterate over an enumerable (Array), mustache.js expects an objects as enumerable items. The implicit iterator pragma enables optional behaviour of allowing literals as enumerable items. Consider this view:

var view = {
  foo: [1, 2, 3, 4, 5, "french"]
};

The following template can iterate over the member foo:

{{%IMPLICIT-ITERATOR}}
{{#foo}}
  {{.}}
{{/foo}}

If you don't like the dot in there, the pragma accepts an option to set your own iteration marker:

{{%IMPLICIT-ITERATOR iterator=bob}}
{{#foo}}
  {{bob}}
{{/foo}}

More Examples and Documentation

See examples/ for more goodies and read the original mustache docs

Command Line

See mustache(1) man page or http://defunkt.github.com/mustache/mustache.1.html for command line docs.

Or just install it as a RubyGem:

$ gem install mustache
$ mustache -h