Skip to content
master
Go to file
Code

Latest commit

 

Git stats

Files

Permalink
Failed to load latest commit information.
Type
Name
Latest commit message
Commit time
src
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

README.md

BEM class names generator

Build Status code style: prettier

Friendly BEM class names generator. Great for React.

Bem-cn (aka BEM Class Name) is extra small (minified+gzipped less than 1.6Kb) and extremely simple client-side library and Node.js module.

Important! Only bem-cn@3.x+ compatible with react@16+. Please do not use version 2.x or lower. More details about the problem.

Inspired by b_.

Justification

I spent a lot of time finding BEM class name generator, that meets my needs:

  • Simple usage with React
  • Support modifiers without value
  • Mix multiple blocks
  • Friendly API

When my efforts had led to naught I've created this micro library.

Install

With Node.js:

npm i --save bem-cn
yarn add bem-cn

Works with webpack and browserify:

// CommonJS
var { block } = require('bem-cn');

// ES6
import { block } from 'bem-cn';

API

const b = block('button');

// Block
b(); // 'button'

// Element
b('icon'); // 'button__icon'

// Modifier
b({ type: 'text' });  // 'button button_type_text'
b({ onlykey: true });  // 'button button_onlykey'
b({ without: false });  // 'button'

b('icon', { name: 'check' }); // 'button__icon button__icon_name_check'

// Mix another classes
b('icon').mix('another'); // 'button__icon another'
b('icon').mix(['one', 'two']); // 'button__icon one two'

// States like in SMACSS: https://smacss.com/book/type-state
b.state({ hidden: true }); // 'button is-hidden'
b.state({ hidden: false }); // 'button'
b.state({ hidden: true, error: true }); // 'button is-hidden is-error'

// More states!
b.is({ loading: true }); // 'button is-loading'
b.has({ content: true }); // 'button has-content'
// Setup custom delimiters
import { setup } from 'bem-cn';

const block = setup({
    el: '~~',
    mod: '--',
    modValue: '-'
});

const b = block('block');

b('element'); // 'block~~element'
b({ mod: 'value' }); // 'block block--mod-value'
// Setup namespace
const block = setup({ ns: 'ns-' });

const b = block('block');

b(); // 'ns-block'
b('element'); // 'ns-block__element'
b({ mod: 'value' }); // 'ns-block ns-block_mod_value'

Try it with React

import block from 'bem-cn';
import React from 'react';
import ReactDOM from 'react-dom';

const b = block('popup');

const Popup = React.createClass({
    render() {
        const { skin, children } = this.props;

        return (
            <div className={b()}>
            	<span className={b('icon')} />
            	<div className={b('content', { skin })}>
            		{children}
            	</div>
            </div>
        );
    }
});

ReactDOM.render(<Popup skin="bright">Hello!</Popup>, target);

/*
<div class="popup">
	<span class="popup__icon"></span>
	<div class="popup__content popup__content_skin_bright">
        Hello!
	</div>
</div>
 */

Troubleshooting

Maigrate to version 3.x

@todo

PropTypes warnings

bem-cn@2.x or lower has specific chainable API. As a result, each call returns function for a further call. But most components are expecting property className as a string and using propTypes object for check this. In this case, you will see a warning. There are the couple of ways to avoid these warnings below.

#1

Use final call without arguments to get a string

<CustomComponent className={b('icon')()} />

#2

Use explicit call of method toString():

<CustomComponent className={b('icon').toString()} />

#3

Use less specific propTypes rules:

let CustomComponent = React.createClass({
    propTypes: {
        className: React.PropTypes.oneOfType([
            React.PropTypes.string,
            React.PropTypes.func
        ])
    },
    // ...
});

ES3 browsers

bem-cn is fully compatible with ES5 browsers. If you are going to support ES3 browsers than just use es5 shim.

About

Friendly BEM-style class name generator, great for React.

Resources

License

Packages

No packages published