bem.js

DOM selection and manipulation using BEM (Block, Element, Modifier).

Install

Install with npm

$ npm i bem.js --save

Usage

Code examples in es6, library is es5 compatible. See doc for full API documentation.

Selecting an element

import BEM from 'bem.js';


// Returns HTMLElement matching .block
BEM.getBEMNode('block');

// Returns HTMLElement matching .block--modifier
BEM.getBEMNode('block', false, 'modifier');

// Returns HTMLElement matching .block__element
BEM.getBEMNode('block', 'element');

// Returns HTMLElement matching .block__element--modifier
BEM.getBEMNode('block', 'element', 'modifier');

// Returns NodeList with HTMLElements matching .block__element--modifier
BEM.getBEMNodes('block', 'element', 'modifier');

// Returns HTMLElement matching .block__element--modifier, child of node
BEM.getChildBEMNode(node, 'block', 'element', 'modifier');

// Returns NodeList with HTMLElements matching .block__element--modifier, children of node
BEM.getChildBEMNodes(node, 'block', 'element', 'modifier');

Building BEM class names

import BEM from 'bem.js';


// Returns '.block'
BEM.getBEMSelector('block');

// Returns '.block.block--modifier'
BEM.getBEMSelector('block', false, 'modifier');

// Returns '.block__element'
BEM.getBEMSelector('block', 'element');

// Returns '.block__element.block__element--modifier'
BEM.getBEMSelector('block', 'element', 'modifier');


// Returns 'block'
BEM.getBEMClassName('block');

// Returns 'block--modifier'
BEM.getBEMClassName('block', false, 'modifier');

// Returns 'block__element'
BEM.getBEMClassName('block', 'element');

// Returns 'block__element--modifier'
BEM.getBEMClassName('block', 'element', 'modifier');

Adding/removing modifiers

import BEM from 'bem.js';


// Adding a modifier
let node = BEM.getBEMClassName('foo');
BEM.addModifier(node, 'bar');  // node.className is now 'foo foo--bar'

// Adding an additional modifier
BEM.addModifier(node, 'baz');  // node.className is now 'foo foo--bar foo--baz'

// Removing a modifier
BEM.removeModifier(node, 'bar');  // node.className is now 'foo foo--baz'

// Toggle a modifier
BEM.toggleModifier(node, 'bar');

// Add/remove modifier based on expression
BEM.toggleModifier(node, 'bar', exp);  // If exp is true, add, remove otherwise
BEM.addModifier(node, 'bar', exp);  // Only add if exp is true
BEM.removeModifier(node, 'bar');  // Only remove if exp is true

Check if HTMLElement has a modifier

import BEM from 'bem.js';


let node = BEM.getBEMNode('foo');  // <article class="foo foo--bar"></article>
BEM.hasModifier(node, 'bar')  // true
BEM.hasModifier(node, 'baz')  // false

let node = BEM.getBEMNode('foo');  // <article class="foo"></article>
BEM.hasModifier(node, 'bar')  // false

Running tests

$ gulp build  // Make sure you test against the latest build
$ gulp lint   // Check for linting errors
$ gulp test   // Run the tests

Contributing

Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.

Author

Maykin Media

• maykinmedia.nl
• github/maykinmedia
• twitter/maykinmedia

License

Copyright © 2016 Maykin Media Licensed under the MIT license.