bem-cx is designed for generating css classNames for use primarily in react components. It doesn't depend on react, so you could use it elsewhere.

Install

npm install bem-cx

Docs

The docs can be found in the docs directory, though they might not make sense without the examples below.

Example

There are two flavors of bem-cx. The first is very simple but requires more typing. The example is in JSX.

import makeBem from 'bem-cx'; // or require('bem-cx').default
const bem = makeBem('Foo');

class Foo {
  render(){
      return (
        <div className={bem}>
          Foo
          <div className={bem.el('Header')}>
            Foo__Header
            <div className={bem.el('Header').el('Title')}>
              Foo__Header__Title
            </div>
          </div>
          <div className={bem.el('Content')}>
            <div className={bem.el('Content').el('Example').mod(true && 'active')}>
              Foo__Content__Example Foo__Content__Example--active
            </div>
            <div className={bem
              .el('Content')
              .el('Example')
              .mod({
                a: true,
                b: false,
                c: false
              })}
              >
              Foo__Content__Example
              Foo__Content__Example--a
              Foo__Content__Example--c
            </div>
          </div>
        </div>
      );
  }
}

This is the same as above but uses CxStack. CxStack has the same api as the above but also provides .elAt takes a level as its first argument.

Level 0 is the root, so direct children of the root node will have the level 1.

This saves you from needing to type everything on the hierarchy for each element. Aside from .mod this is the main value proposition of this library.

import {CxStack} from 'bem-cx'; // or require('bem-cx').CxStack

class Foo {
  render(){
      const bem = new CxStack('Foo');
      return (
        <div className={bem}>
          Foo
          <div className={bem.elAt(1, 'Header')}>
            Foo__Header
            <div className={bem.elAt(2, 'Title')}>
              Foo__Header__Title
            </div>
          </div>
          <div className={bem.elAt(1, 'Content')}>
            <div className={bem.elAt(2, 'Example').mod(true && 'active')}>
              Foo__Content__Example Foo__Content__Example--active
            </div>
            <div className={bem
              .elAt(2, 'Example')
              .mod({
                a: true,
                b: false,
                c: false
              })}
              >
              Foo__Content__Example
              Foo__Content__Example--a
              Foo__Content__Example--c
            </div>
          </div>
        </div>
      );
  }
}