better-BEM

In contrast to what the package name suggests, better-BEM may not actually be better than other packages handling BEM className generation. better-BEM does support className maps as imported with CSS Modules.

Why

A quick Google search for a package which handles dynamic className generation according to BEM methodology (block__element--modifier) and which supports className maps didn't yield any results.

Usage

# install
npm i better-bem

// import
import BEM from 'better-bem';

BEM( classNames [, classNameMap [, strictClassNameMap ] ] )

// output:
{
	 cn,  // string className
	 el,  // function el( classNames )
	 mod, // function mod( classNames )
}

parameters

classNames

default value: []

accepts: String, object or array of strings and/or objects

classNames	.cn output
"foobar"	"foobar"
["foobar", "lorem ipsum"]	"foobar lorem ipsum"
" foo bar "	"foo bar"
{ foo: false, bar: "truthy value" }	"bar"
["foo bar", { lorem: true }, "ipsum"]	"foo bar lorem ipsum"
mod() only: { property: "value" }	"property-value"

classNameMap

default value: {}

accepts: Object with input className to output className mapping

strictClassNameMap

default value: true

accepts: Boolean

When classNameMap is not empty and strictClassNameMap is true all inputted classNames which aren't in the classNameMap are ignored. When strictClassNameMap is false they will be outputted.

classNames	classNameMap	strictClassNameMap	.cn output
"foo bar"	{ foo: "output-foo" }	true	"output-foo"
"foo bar"	{ foo: "output-foo" }	false	"output-foo bar"

Chaining

// Block classname
const block = BEM('block');
block.cn;
// => "block"

// Underlying element classname
const element = block.el('element');
element.cn;
// => "block__element"

const modifiers = ['error', { color: 'red', valid: false }];

// Block classname with modifiers
const modifiedBlock = block.mod(modifiers);
modifiedBlock.cn;
// => "block block--error block--color-red"

const modifiedElement = element.mod(modifiers);
modifiedElement.cn;
// => "block__element block__element--error block__element--color-red"