Drupal 8 Theming

Week 4

Advanced Twig

Using variables in templates

{# comment #}

{{ variable }}

{% functional %}

{# comment #}

{# 
    this is a twig comment
    twig comment is not rendered in the DOM
#}

{{ variable }}

{{ variable }}

{% functional %}

{% set foo = bar %}

In a template

{#
/**
 * @file
 * Theme override to display a region.
 *
 * Available variables:
 * - content: The content for this region, typically blocks.
 * - attributes: HTML attributes for the region <div>.
 * - region: The name of the region variable as defined in the theme's
 *   .info.yml file.
 *
 * @see template_preprocess_region()
 */
#}
{%
  set classes = [
    'region',
    'region-' ~ region|clean_class,
  ]
%}
{% if content %}
  <div{{ attributes.addClass(classes) }}>
    {{ content }}
  </div>
{% endif %}

Example

using node.html.twig

node.html.twig

{#
/**
 * @file
 * Theme override to display a node.
 *
 * Available variables:
 * - node: The node entity with limited access to object properties and methods.
 *   Only method names starting with "get", "has", or "is" and a few common
 *   methods such as "id", "label", and "bundle" are available. For example:
 *   - node.getCreatedTime() will return the node creation timestamp.
 *   - node.hasField('field_example') returns TRUE if the node bundle includes
 *     field_example. (This does not indicate the presence of a value in this
 *     field.)
 *   - node.isPublished() will return whether the node is published or not.
 *   Calling other methods, such as node.delete(), will result in an exception.
 *   See \Drupal\node\Entity\Node for a full list of public properties and
 *   methods for the node object.
 * - label: The title of the node.
 * - content: All node items. Use {{ content }} to print them all,
 *   or print a subset such as {{ content.field_example }}. Use
 *   {{ content|without('field_example') }} to temporarily suppress the printing
 *   of a given child element.
 * - author_picture: The node author user entity, rendered using the "compact"
 *   view mode.
 * - metadata: Metadata for this node.
 * - date: Themed creation date field.
 * - author_name: Themed author name field.
 * - url: Direct URL of the current node.
 * - display_submitted: Whether submission information should be displayed.
 * - attributes: HTML attributes for the containing element.
 *   The attributes.class element may contain one or more of the following
 *   classes:
 *   - node: The current template type (also known as a "theming hook").
 *   - node--type-[type]: The current node type. For example, if the node is an
 *     "Article" it would result in "node--type-article". Note that the machine
 *     name will often be in a short form of the human readable label.
 *   - node--view-mode-[view_mode]: The View Mode of the node; for example, a
 *     teaser would result in: "node--view-mode-teaser", and
 *     full: "node--view-mode-full".
 *   The following are controlled through the node publishing options.
 *   - node--promoted: Appears on nodes promoted to the front page.
 *   - node--sticky: Appears on nodes ordered above other non-sticky nodes in
 *     teaser listings.
 *   - node--unpublished: Appears on unpublished nodes visible only to site
 *     admins.
 * - title_attributes: Same as attributes, except applied to the main title
 *   tag that appears in the template.
 * - content_attributes: Same as attributes, except applied to the main
 *   content tag that appears in the template.
 * - author_attributes: Same as attributes, except applied to the author of
 *   the node tag that appears in the template.
 * - title_prefix: Additional output populated by modules, intended to be
 *   displayed in front of the main title tag that appears in the template.
 * - title_suffix: Additional output populated by modules, intended to be
 *   displayed after the main title tag that appears in the template.
 * - view_mode: View mode; for example, "teaser" or "full".
 * - teaser: Flag for the teaser state. Will be true if view_mode is 'teaser'.
 * - page: Flag for the full page state. Will be true if view_mode is 'full'.
 * - readmore: Flag for more state. Will be true if the teaser content of the
 *   node cannot hold the main body content.
 * - logged_in: Flag for authenticated user status. Will be true when the
 *   current user is a logged-in member.
 * - is_admin: Flag for admin user status. Will be true when the current user
 *   is an administrator.
 *
 * @see template_preprocess_node()
 *
 * @todo Remove the id attribute (or make it a class), because if that gets
 *   rendered twice on a page this is invalid CSS for example: two lists
 *   in different view modes.
 */
#}
{%
  set classes = [
    'node',
    'node--type-' ~ node.bundle|clean_class,
    node.isPromoted() ? 'node--promoted',
    node.isSticky() ? 'node--sticky',
    not node.isPublished() ? 'node--unpublished',
    view_mode ? 'node--view-mode-' ~ view_mode|clean_class,
  ]
%}
{{ attach_library('classy/node') }}
<article{{ attributes.addClass(classes) }}>

  {{ title_prefix }}
  {% if not page %}
    <h2{{ title_attributes }}>
      <a href="{{ url }}" rel="bookmark">{{ label }}</a>
    </h2>
  {% endif %}
  {{ title_suffix }}

  {% if display_submitted %}
    <footer class="node__meta">
      {{ author_picture }}
      <div{{ author_attributes.addClass('node__submitted') }}>
        {% trans %}Submitted by {{ author_name }} on {{ date }}{% endtrans %}
        {{ metadata }}
      </div>
    </footer>
  {% endif %}

  <div{{ content_attributes.addClass('node__content') }}>
    {{ content }}
  </div>

</article>

Comment block: READ

{#
/**
 * @file
 * Theme override to display a node.
 *
 * Available variables:
 * - node: The node entity with limited access to object properties and methods.
 *   Only method names starting with "get", "has", or "is" and a few common
 *   methods such as "id", "label", and "bundle" are available. For example:
 *   - node.getCreatedTime() will return the node creation timestamp.
 *   - node.hasField('field_example') returns TRUE if the node bundle includes
 *     field_example. (This does not indicate the presence of a value in this
 *     field.)
 *   - node.isPublished() will return whether the node is published or not.
 *   Calling other methods, such as node.delete(), will result in an exception.
 *   See \Drupal\node\Entity\Node for a full list of public properties and
 *   methods for the node object.
 * - label: The title of the node.
 * - content: All node items. Use {{ content }} to print them all,
 *   or print a subset such as {{ content.field_example }}. Use
 *   {{ content|without('field_example') }} to temporarily suppress the printing
 *   of a given child element.
 * - author_picture: The node author user entity, rendered using the "compact"
 *   view mode.
 * - metadata: Metadata for this node.
 * - date: Themed creation date field.
 * - author_name: Themed author name field.
 * - url: Direct URL of the current node.
 * - display_submitted: Whether submission information should be displayed.
 * - attributes: HTML attributes for the containing element.
 *   The attributes.class element may contain one or more of the following
 *   classes:
 *   - node: The current template type (also known as a "theming hook").
 *   - node--type-[type]: The current node type. For example, if the node is an
 *     "Article" it would result in "node--type-article". Note that the machine
 *     name will often be in a short form of the human readable label.
 *   - node--view-mode-[view_mode]: The View Mode of the node; for example, a
 *     teaser would result in: "node--view-mode-teaser", and
 *     full: "node--view-mode-full".
 *   The following are controlled through the node publishing options.
 *   - node--promoted: Appears on nodes promoted to the front page.
 *   - node--sticky: Appears on nodes ordered above other non-sticky nodes in
 *     teaser listings.
 *   - node--unpublished: Appears on unpublished nodes visible only to site
 *     admins.
 * - title_attributes: Same as attributes, except applied to the main title
 *   tag that appears in the template.
 * - content_attributes: Same as attributes, except applied to the main
 *   content tag that appears in the template.
 * - author_attributes: Same as attributes, except applied to the author of
 *   the node tag that appears in the template.
 * - title_prefix: Additional output populated by modules, intended to be
 *   displayed in front of the main title tag that appears in the template.
 * - title_suffix: Additional output populated by modules, intended to be
 *   displayed after the main title tag that appears in the template.
 * - view_mode: View mode; for example, "teaser" or "full".
 * - teaser: Flag for the teaser state. Will be true if view_mode is 'teaser'.
 * - page: Flag for the full page state. Will be true if view_mode is 'full'.
 * - readmore: Flag for more state. Will be true if the teaser content of the
 *   node cannot hold the main body content.
 * - logged_in: Flag for authenticated user status. Will be true when the
 *   current user is a logged-in member.
 * - is_admin: Flag for admin user status. Will be true when the current user
 *   is an administrator.
 *
 * @see template_preprocess_node()
 *
 * @todo Remove the id attribute (or make it a class), because if that gets
 *   rendered twice on a page this is invalid CSS for example: two lists
 *   in different view modes.
 */
#}

Set variables

{%
  set classes = [
    'node',
    'node--type-' ~ node.bundle|clean_class,
    node.isPromoted() ? 'node--promoted',
    node.isSticky() ? 'node--sticky',
    not node.isPublished() ? 'node--unpublished',
    view_mode ? 'node--view-mode-' ~ view_mode|clean_class,
  ]
%}

Attach libraries

{{ attach_library('classy/node') }}

Use vars, build template

<article{{ attributes.addClass(classes) }}>

  {{ title_prefix }}
  {% if not page %}
    <h2{{ title_attributes }}>
      <a href="{{ url }}" rel="bookmark">{{ label }}</a>
    </h2>
  {% endif %}
  {{ title_suffix }}

  {% if display_submitted %}
    <footer class="node__meta">
      {{ author_picture }}
      <div{{ author_attributes.addClass('node__submitted') }}>
        {% trans %}Submitted by {{ author_name }} on {{ date }}{% endtrans %}
        {{ metadata }}
      </div>
    </footer>
  {% endif %}

  <div{{ content_attributes.addClass('node__content') }}>
    {{ content }}
  </div>

</article>

Using attributes in templates

Attributes

<div {{ attributes }}>

 

class="foo"

data-drupal-foo

aria-hidden="true"

Addclass

{%
 set classes = [
 ‘field-' ~ field_name|clean_class ~ '
 ]
%}
<div {{ attributes.addClass(classes) }}>…</div>
<div class=“field-tags”>…

Removeclass

<div {{ attributes.removeClass('classname') }}>

<div class="nickelback">

CORE

MODULE

CLASSY

<div class="core">

CORE

MODULE

CLASSY

<div class="core nickelback">

$var['attributes']->addClass('nickelback')

CORE

MODULE

CLASSY

<div class="core nickelback theme">

{{ attributes.addClass('theme') }}

CORE

MODULE

CLASSY

<div class="core theme">

{{ attributes.removeClass('nickelback') }}

CORE

MODULE

CLASSY

<div class="theme">

{{ attributes.removeClass('nickelback','core') }}

<div>

<div {{ attributes.removeClass('nickelback') }}>

<div class="nickelback">
<div {{
    attributes
        .removeClass('nickelback')
        .addClass('rush')
        .setAttribute('id', 'top')
    }}>
<div id="top" class="rush">

Attributes

More functions

.addClass()

.removeClass()

.setAttribute()

.removeAttribute()

.hasClass()

Create attributes

create_attribute()

{% set my_attribute = create_attribute() %}
{%
  set my_classes = [
    'kittens',
    'llamas',
    'puppies',
  ]
%}
<div{{ my_attribute.addClass(my_classes).addAttribute('id', 'myUniqueId') }}>
  {{ content }}
</div>

More docs

Exercise

Revisit last weeks templates and set the classes properly: 

use attributes

Using filters in templates

Filters

{% filter upper %}
    uppercase is awesome
{% endfilter %}
{{ variable|upper }}

Hardcoded text

Drupal variable

More filters

{{ var|clean_class }}
{{ var|clean_id }}
{{ var|format_date }}
{{ var|raw }}
{{ var|render }}
{{ var|safe_join }}
{{ var|without }}

Drupal only filters

<a 
    href="{{ url('<front>') }}" 
    title="{{ 'Home'|t }}" 
    rel="home" 
    class="site-logo"
></a>

Translation

{% trans %}Translatable text{% endtrans %}

Drupal only filters

Placeholder

{% trans %}
    Submitted on {{ date|placeholder }}
{% endtrans %}

Without filter

{{ content|without('field') }}

Without filter example

{{ content }}

{{ text }}

{{ tags }}

{{ image }}

{{ content|without('image') }}

{{ content|without('image') }}

{{ text }}

{{ tags }}

{{ content.image }}

{{ content|without('image', 'tags') }}

{{ content|without('image', 'tags') }}

{{ text }}

{{ content.tags }}

{{ content.image }}

{{ content.new }}

{{ content|without('image', 'tags') }}

{{ text }}

{{ content.tags }}

{{ content.image }}

{{ new }}

In code

In code

Finding field names

Filter docs

Exercise

Create a template for Article Card view-mode

Create wrappers for the image & other content

Context

  1. Go to the /articles page
  2. Inspect the view: notice the views-row structure
    • Each views-row contains a node--type-article




       

  3. Create a template that targets only this view-mode: card​​

  4. Change the structure: move the image to a new wrapper

Result:

Result:

Exercise

Print an image as a background-image

Context

We want our teaser image to be shown as a background-image.

 

Try and debug the image field and print the image-url as inline style:

 

 

 

 

Pro tip: Use kint() debugging!

<article{{ attributes.addClass(classes) }} style="background: url('{{ image_url }}');">
<article class="node" style="background: url('/sites/default/files/image.jpg');">

Lets get to it!

Drupal 8 Theming IMD W4

By Pieter Mathys

Drupal 8 Theming IMD W4

Les week 4 D8IMD Theming

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