Twig Defer Block

This Twig extension adds defer block rendering. A defer block allows you to defer a block within its current context but show the output at a later stage in the template. By default, the defer block will append information based on its reference name, this allows you to define multiple defer block which are then output at a single place.

Example

{% defer js %}
    <script src="1.js" />
{% enddefer %}
{% defer js %}
    <script src="2.js" />
{% enddefer %}

<p>Hello</p>
{{ defer('js') }}

Output:

<p>Hello</p>
    <script src="1.js" />
    <script src="2.js" />

Example with unique

When using the defer block, a second name can be given. It can be a variable or a string, when using a variable make sure it has a scalar value. A unique name allows you to only render a block once. (Note: This will always pick the first block with the second name)

{% set bar = ['1', '2'] %}
{% for x in xs %}
    {% defer js 'once' %}
        <script src="once.js" />
    {% enddefer %}
    {% defer js x %}
        <script src="once_{x}.js" />
    {% enddefer %}
    {% defer js %}
        <script src="{x}.js" />
    {% enddefer %}
{% endfor %}

{% for x in xs %}
    {% defer js x %}
        <script src="once_{x}.js" />
    {% enddefer %}
    <li>x</li>
{% endfor %}
{{ defer('js') }}

Output:

<ul>
    <li>1</li>
    <li>2</li>
</ul>
        <script src="once.js" />
        <script src="once_1.js" />
        <script src="1.js" />
        <script src="once_2.js" />
        <script src="2.js" />

Other options:

A different defer implementation was made by Eugene Leonovich called rybakit/twig-extensions-deferred.