Skip to content
Fetching contributors…
Cannot retrieve contributors at this time
193 lines (126 sloc) 5.95 KB


Built-in Tags


Makes the current template extend a parent template. This tag must be the first item in your template.

See Template inheritance for more information.


Defines a block in a template that can be overridden by a template extending this one and/or will override the current template's parent template block of the same name.

See Template inheritance for more information.


Inject the content from the current block in the parent template into the child template.

See Template inheritance for more information.


Includes a template in it's place. The template is rendered within the current context. Does not use and {% endinclude %}.

{% include template_path %}
{% include "path/to/template.js" %}


For loops have 4 special context variables accessible inside of the loop:

{% for x in y %}
    {% if forloop.first %}<ul>{% endif %}
    <li>{% forloop.index %} - {% forloop.key %}: {{ x }}</li>
    {% if forloop.last %}</ul>{% endif %}
{% endfor %}
  • forloop.index: the zero-indexed spot in the iterator.
  • forloop.key: if the iterator is an object, this will be the key of the current item, otherwise it will be the same as the forloop.index.
  • forloop.first: true if the current object is the first in the object or array.
  • forloop.last: true if the current object is the last in the object or array.

You can also apply filters to the object that you are iterating over.

{% for x in y|reverse %}
    The array `y` will first be reversed before looping over it.
{% endfor %}


For loops have a special tag available to them called {% empty %}.

If the loop object is empty or length === 0, the content following the empty tag will be rendered.

{% for person in people %}
    {{ person }}
{% empty %}
    There are no people yet!
{% endfor %}


All normal JavaScript-valid if statements are supported, including some extra helpful syntaxes:

{% if x %}{% endif %}
{% if !x %}{% endif %}
{% if not x %}{% endif %}

{% if x and y %}{% endif %}
{% if x && y %}{% endif %}
{% if x or y %}{% endif %}
{% if x || y %}{% endif %}
{% if x || (y && z) %}{% endif %}

{% if x [operator] y %}
    Operators: ==, !=, <, <=, >, >=, ===, !==
{% endif %}
{% if x == 'five' %}
    The operands can be also be string or number literals
{% endif %}
{% if x|length === 3 %}
    You can use filters on any operand in the statement.
{% endif %}

{% if x in y %}
    If x is a value that is present in y, this will return true.
{% endif %}

else and else if

Also supports using the {% else %} and {% else if ... %} tags within an if-block. Using {% else [if ...] %} anywhere outside an immediate parent if-block will throw an exception.

{% if foo %}
    Some content.
{% else if "foo" in bar %}
    Content if the array `bar` has "foo" in it.
{% else %}
    Fallback content.
{% endif %}


The autoescape tag accepts two controls:

  1. on or off: (default is on if not provided). These either turn variable auto-escaping on or off for the contents of the filter, regardless of the global setting.
  2. escape-type: optionally include "js" to escape variables safe for JavaScript

For the following contexts, assume:

some_html_output = '<p>Hello "you" & \'them\'</p>';

So the following:

{% autoescape off %}
    {{ some_html_output }}
{% endautoescape %}

{% autoescape on %}
    {{ some_html_output }}
{% endautoescape %}

{% autoescape on "js" %}
    {{ some_html_output }}
{% endautoescape %}

Will output:

<p>Hello "you" & 'them'</p>

&lt;p&gt;Hello &quot;you&quot; &amp; &#39;them&#39; &lt;/p&gt;

\u003Cp\u003EHello \u0022you\u0022 & \u0027them\u0027\u003C\u005Cp\u003E


It is also possible to set variables in templates.

{% set foo = [0, 1, 2, 3, 4, 5] %}
{% for num in foo %}
    <li>{{ num }}</li>
{% endfor %}


Macros are custom, reusable methods for content-generation that are defined in templates.


One of the most common use-case for macros is form inputs. To start, define your input macro somewhere in your template scope (the top of a template, or an included template is a good spot):

{% macro input type name id label value error %}
    <label for="{{ name }}">{{ label }}</label>
    <input type="{{ type }}" name="{{ name }}" id="{{ id }}" value="{{ value }}"{% if error %} class="error"{% endif %}>
{% endmacro %}

Somewhere later in your template, invoke the macro using a variable:

<div>{{ input("text", "fname", "fname", "First Name", fname.value, fname.errors) }}</div>
<div>{{ input("text", "lname", "lname", "Last Name", lname.value, lname.errors) }}</div>

Your output may look like this:

    <label for="fname">First Name</label>
    <input type="text" name="fname" id="fname" value="Paul">
    <label for="lname">Last Name</label>
    <input type="text" name="lname" id="lname" value="" class="error">


The import tag is specifically designed for importing macros into your template with a specific context scope. This is very useful for keeping your macros from overriding template context that is being injected by your server-side page generation.


Assuming the macro input exists in formmacros.html, you can run the macro by using {{ form.input }} as follows:

{% import 'formmacros.html' as form %}

{# this will run the input macro #}
{{ form.input("text", "name") }}

{# this, however, will NOT output anything because the macro is scoped to the "form" object: #}
{{ input("text", "name") }}

Custom Tags

Swig has support for you to write your own custom tags. For more information, see the Custom Tags Documentation.

Jump to Line
Something went wrong with that request. Please try again.