~400 bytes gzipped

Bem is a higher-order-function... (it's just a function that creates a function)

bem = BEM(Object): // Object { prefix: String, block: String } => Returns function

bem(String, Array|String|object, Array|String|Object)

Primary Options

• block mandatory : String
• prefix optional : String default ``

Secondary Options

• 1st argument (element) optional : String
• 2nd argument (modifier) optional : String | Object | Array
• 3rd argument (util) optional : String | Object | Array

Using Objects

The class name is built using the keys of the Object. The values are evaluated, if they are falsey, they're ignored.

{ 
  'potential-class': false, // ignored
  'another-class': true, // added
}

Using Arrays

The class name is built using the values of the Array.

[ 'potential-class', 'another-class' ]

Usage

const className = Bem({  prefix: 'ac-', block: 'my-component' })
...
<div className={ className() } /> // returns 'ac-my-component'
<div className={ className('element') } />  // returns 'ac-my-component__element '
<div className={ className('element', 'modifier') } />  // returns 'ac-my-component__element ac-my-component__element--modifier'
<div className={ className('element', 'modifier', 'util-class') } />  // returns 'ac-my-component__element ac-my-component__element--modifier util-class'

If you do not need an early argument, but do need a later argument, use falsey

const className = Bem({  prefix: 'ac-', block: 'my-component' })
...
<div className={ className(null, 'modifier') } /> // returns 'ac-my-component ac-my-component--modifier'
<div className={ className('element', null, 'util') } />  // returns 'ac-my-component__element util'
<div className={ className(null, null, 'util') } />  // returns 'ac-my-component util'