pug-bem

A plugin that adds BEM shortcuts to Pug

• BEM
• Pug
• for Bootstrap

New! v1.2.0

Now you can specify your own prefixes for blocks in the b property:

var bem = require('pug-bem');
 
// block prefix
bem.b = 'my-';

or

// default 'b-'
bem.b = true;

The prefix name can consist of letters, numbers, underscores, and hyphens. After that, only classes that begin with your prefix will be considered when parsing the BEM blocks. Classes of blocks without a prefix will be skipped at any depth of nesting elements. This will solve the problem associated with the use of external css-libraries, such as Bootstrap, with a large depth of nesting elements. For example:

no prefix:

test.pug

.block
  .row
    .col-lg-8.col-xl-4
      .row
        .col-lg-8.col-xl-3
          ._elem1
    .col-lg-4.col-xl-8
      ._elem2

will be compiled to:

<div class="block">
  <div class="row">
    <div class="col-lg-8 col-xl-4">
      <div class="row">
        <div class="col-lg-8 col-xl-3">
          <!-- the block is the closest parent element with the class 'col-lg-8' in the file 'test.pug' -->
          <div class="col-lg-8__elem1"></div>
        </div>
      </div>
    </div>
    <div class="col-lg-4 col-xl-8">
      <!-- the block is the closest parent element with the class 'col-lg-4' in the file 'test.pug' -->
      <div class="col-lg-4__elem2"></div>
    </div>
  </div>
</div>

user prefix:

gulpfile.js

var bem = require('pug-bem');
bem.b = true // default 'b-'

test.pug

//- add prefix to block name
.b-block
  .row
    .col-lg-8.col-xl-4
      .row
        .col-lg-8.col-xl-3
          ._elem1
    .col-lg-4.col-xl-8
      ._elem2

will be compiled to:

<!-- user prefix will not fall into the final html -->
<div class="block">
  <div class="row">
    <div class="col-lg-8 col-xl-4">
      <div class="row">
        <div class="col-lg-8 col-xl-3">
         <!-- the block is an element with the prefix 'b-' in the file 'test.pug' -->
          <div class="block__elem1"></div>
        </div>
      </div>
    </div>
    <div class="col-lg-4 col-xl-8">
      <!-- the block is an element with the prefix 'b-' in the file 'test.pug' -->
      <div class="block__elem2"></div>
    </div>
  </div>
</div>

another example:

//- when using custom prefixes, they must be added to the name of each BEM block.
//- block classes without a prefix are not taken into account in the BEM namespace when compiling!
.b-block1
  .class1.class2
    .class3
      ._elem1
    .b-block2
      ._elem2

will be compiled to:

<div class="block1">
  <div class="class1 class2">
    <div class="class3">
      <div class="block1__elem1"></div>
    </div>
    <div class="block2">
      <div class="block2__elem2"></div>
    </div>
  </div>
</div>

Install

npm install pug pug-bem --save-dev

• Gulp
• Webpack

Setup

var pug = require('pug');
var bem = require('pug-bem');
 
// Create object options
var options = {
  plugins: [bem]
}
 
// Compile a function
var fn = pug.compile('string of pug', options);

• Options

Example Usage

Block

.block

.header
form.search-form
 
.header
    nav.menu

result:

<div class="header"></div>
<form class="search-form"></form>
 
<div class="header">
    <nav class="menu"></nav>

---

Element

._element

form.search-form
    input._input
    button._button Search

result:

<form class="search-form">
    <input class="search-form__input">
    <button class="search-form__button">Search</button>
</form>

---

Modifier

.-modifier

Boolean

.-boolean

form.search-form.-focused
    button._button.-disabled Search

result:

<form class="search-form search-form--focused">
    <button class="search-form__button search-form__button--disabled">Search</button>
</form>

Key_Value

.-key_value

form.search-form.-theme_islands
    button._button.-size_m Search

result:

<form class="search-form search-form--theme_islands">
    <button class="search-form__button search-form__button--size_m">Search</button>
</form>

---

Mix

.block._element

.header
    form.search-form._search-form

result:

<div class="header">
    <form class="search-form header__search-form"></form>
</div>

---

Example

header.header
    nav.menu
        a(href="#")._logo Company
        .list
            a._item.-active(href="#") Home
            a._item(href="#") News
            a._item(href="#") Gallery
            a._item(href="#") Partners
            a._item(href="#") About
            a._item(href="#") Contacts
    h1._title Hello, World!
    .myslider._myslider
        ._slide Content
        ._slide.-active Content
        ._slide Content
    p._text Good weather

result:

<header class="header">
    <nav class="menu">
        <a class="menu__logo" href="#">Company</a>
        <div class="list">
            <a class="list__item list__item--active" href="#">Home</a>
            <a class="list__item" href="#">News</a>
            <a class="list__item" href="#">Gallery</a>
            <a class="list__item" href="#">Partners</a>
            <a class="list__item" href="#">About</a>
            <a class="list__item" href="#">Contacts</a>
        </div>
    </nav>
    <h1 class="header__title">Hello, World!</h1>
    <div class="myslider header__myslider">
        <div class="myslider__slide">Content</div>
        <div class="myslider__slide myslider__slide--active">Content</div>
        <div class="myslider__slide">Content</div>
    </div>
    <p class="header__text">Good weather</p>
</header>

Options

var bem = require('pug-bem');
 
// element separator
bem.e = 'string';
 
// modifier separator
bem.m = 'string';

Example

bem.e = '**';

form.search-form
    input._input

result:

<form class="search-form">
    <input class="search-form**input">
</form>

---

bem.m = '++';

form.search-form.-focused

result:

<form class="search-form search-form++focused"></form>

License

ISC License

Author

Legostaev Vadim ([e-mail])