babel-plugin-transform-jsx-bemed

Babel plugin for BEM class names generation in JSX. It was developed for using in React in combination with postcss plugin.

Install

Just require it as any other babel plugin and add bemed package to your dependencies (so Webpack/Brunch.io/etc. can use it for frontend).

$ npm install babel-plugin-transform-jsx-bemed --save-dev
$ npm install bemed --save

{
  presets: ['es2015'],
  plugins: ['transform-jsx-bemed']
}

Usage

Just add BEM properties into your tag and plugin will construct className for you. className will be a JavaScript expression which calls function from bemed. Header will have this function definition, so it just works out of the box by default. If className is already in tag then nothing will be done (for back-compatibility).

Properties

block Block property. Must be a string.

elem Element property. Must be a string.

mods Modifier property. Can be a string or JavaScript expressions (inside { }). Expression must return string, array or object.

mix Mixin property. Can be a string or JavaScript expressions (inside { }). Expression must return string or array.

Scopes

block property creates a scope and should be used only for top-level JSX tag. Can be omitted if JSX is placed inside class or named arrow function.

Examples

Base usage

Input

<div block="Main" mix="panel" mods={{ warning: true }}>
  <div elem="header" mods="header">Title</div>
  <div elem="body">Text</div>
</div>

Output

<div className={_bem("Main", null, { warning: true }, "panel")}>
  <div className={_bem("Main", "header", "header")}>Title</div>
  <div className={_bem("Main", "body")}>Text</div>
</div>

Input

const Message = ({ type, title, text}) => {
  return <div mods={{ type }} >
    <div elem="header">{ title }</div>
    <div elem="body">{ text }</div>
  </div>
}

Output

const Message = ({ type, title, text }) => {
  return <div className={_bem("Message", null, { type })}>
    <div className={_bem("Message", "header")}>{title}</div>
    <div className={_bem("Message", "body")}>{text}</div>
  </div>;
};

Input

class Message extends Component {
  ...
  render() {
    ...
    return <div mods={this.getMods()}>
      <div elem="header">{ title }</div>
      <div elem="body">{ text }</div>
    </div>
  }
}

Output

class Message extends Component {
  ...
  render() {
    ...
    return <div className={_bem("Message", null, this.getMods())}>
      <div className={_bem("Message", "header")}>{title}</div>
      <div className={_bem("Message", "body")}>{text}</div>
    </div>;
  }
}

Options

rules

Set custom properties naming. Default is

properties: {
  block: 'block',
  element: 'elem',
  modifiers: 'mods',
  mixin: 'mix'
}

separators

Set custom bem separators. Default is

separators: {
  element: '__',
  modifier: '--',
  value: '-'
}