README

BEM — is a methodology that helps you to create reusable components and code sharing in front‑end development

Usage

Create a class instance to represent your BEM model. Pass the "block" as the constructor argument.

$bem = new \AKlump\Bem\Fluent\Bem('foo');

All methods return an object instance that can be typecast to a string. Or, you can also call toString() or toArray() as appropriate; see \AKlump\Bem\Fluent\Interfaces\OutputInterface for details. All of the following produce the same output.

(string) $bem->block(); // foo
strval($bem->block()); // foo
$bem->block()->toString(); // foo

For simplicity any remaining examples will show only the first form.

The Basic Four

(string) $bem->block(); // "foo"
(string) $bem->element('content'); // "foo__content"
(string) $bem->block()->modifier('has-image'); // "foo--has-image"
(string) $bem->element()->modifier('content', 'has-image'); // "foo__content--has-image"

For Javascript Purposes

(string) $bem->block()->js(); // "js-foo"
(string) $bem->element('content')->js(); // "js-foo__content"

Convenience Syntax

There are some conveniences you should take note of; pay special attention to the plus* methods.

// In both cases "foo js-foo" === $classes.
$classes = $bem->block() . ' ' . $bem->block()-js();
$classes = $bem->block()->plusJs();

// In both cases "foo foo--bar" === $classes.
$classes = $bem->block() . ' ' . $bem->block()->modifier('bar);
$classes = $bem->block()->plusModifier('bar);

// In both cases "foo foo--bar js-foo js-foo--bar" === $classes.
$classes = implode(' ', [
  $bem->block(),
  $bem->block()->modifier('bar),
  $bem->block()->js(),
  $bem->block()->modifier('bar)->js(),
]);
  
$classes = $bem->block()->plusModifier('bar)->plusJs()

"Global" Innovation

You'll find an innovation in this project called global. It can be used to target common parts across all blocks at once. Refer to the example below where component and component__content represent the global block and global element, respectively. This innovation, in this case, allows you to target all three components' content in a single line of CSS. It can be thought of as a means of grouping. Use the the plusGlobal() method for this feature.

<section>
  <div class="story component">
    <div class="story__content component__content"></div>
  </div>
  <div class="film component">
    <div class="film__content component__content"></div>
  </div>
  <div class="copy component">
    <div class="copy__content component__content"></div>
  </div>
</section>

.component__content {
  width: 900px;
  margin: auto;
}

$story = new \AKlump\Bem\Fluent\Bem('story', 'component');
$film = new \AKlump\Bem\Fluent\Bem('film', 'component');
$copy = new \AKlump\Bem\Fluent\Bem('copy', 'component');

$story->element('content')->plusGlobal(); // "story__content component__content"
$film->element('content')->plusGlobal(); // "film__content component__content"
$copy->element('content')->plusGlobal(); // "copy__content component__content"

Casting to Array

Given a complex chain as shown next, you can see the helpfulness of the plus* methods and why you might want to use the toArray() method.

$bem = new \AKlump\Bem\Fluent\Bem('foo', 'components');
$classes = $bem->element('content')
  ->plusModifier('first')
  ->plusGlobal()
  ->plusJs()
  ->toArray();

$classes === [
  'foo__content',
  'foo__content--first',
  'js-foo__content',
  'js-foo__content--first',
  'js-components__content',
  'js-components__content--first',
  'components__content',
  'components__content--first',
];

Customizing Output Style

To alter the way the classes are formatted, create a new, custom class implementing \AKlump\Bem\Styles\StyleInterface for control of the processing and output of the classes, including the division characters. Look to \AKlump\Bem\Styles\Official for a model. Pass your custom style to \AKlump\Bem\Fluent\Bem when constructing.

Usage With Twig

Themers

{{ bem_set_global('component') }}
{{ bem_set_block('story-section') }}
<body>
<h1>Twig Extension Example</h1>

<pre>
{% set classes = [
  bem_block().plus_js(),
  bem_block().modifier('th-summary'),
  bem_block().modifier('lang-en'),
] %}
&lt;section>
  &ltdiv class="{{ classes|join(' ') }}">
    &lt;div class="{{ bem_element('width').plus_global() }}">
      &lt;div class="{{ bem_element('item').plus_modifier('first') }}">&lt;/div>
      &lt;div class="{{ bem_element('item') }}">&lt;/div>
      &lt;div class="{{ bem_element('item').plus_modifier('last') }}">&lt;/div>
    &lt;/div>
  &lt;/div>
&lt;/section>
</pre>
</body>

<section>
  <div class="story-section js-story-section story-section--th-summary story-section--lang-en">
    <div class="story-section__width component__width">
      <div class="story-section__item story-section__item--first"></div>
      <div class="story-section__item"></div>
      <div class="story-section__item story-section__item--last"></div>
    </div>
  </div>
</section>

Developers

See \AKlump\Bem\Twig\BemExtension

Contributing

If you find this project useful... please consider making a donation.

aklump / bem

Maintainers

Details