postcss-namespace-selector

Prefix every CSS selector with a custom namespace .a => .namespace .a

Table of Contents

• Install
• Usage with PostCSS
• Usage with Webpack
• Options
• Maintainer
• Contribute
• License

Install

$ npm install postcss-namespace-selector

Usage with PostCSS

const prefixer = require('postcss-namespace-selector')
 
// css to be processed
const css = fs.readFileSync("input.css", "utf8")
 
const out = postcss().use(prefixer({
  prefix: '.some-selector',
  exclude: ['.c'],
 
  // Optional transform callback for case-by-case overrides
  transform: function (prefix, selector, prefixedSelector) {
    if (selector === 'body') {
      return 'body' + prefix;
    } else {
      return prefixedSelector;
    }
  }
})).process(css).css

Using the options above and the CSS below...

body {
  background: red;
}
 
.a, .b {
  color: aqua;
}
 
.c {
  color: coral;
}

You will get the following output

body.some-selector {
  background: red;
}
 
.some-selector .a, .some-selector .b {
  color: aqua;
}
 
.c {
  color: coral;
}

Usage with webpack

Use it like you'd use any other PostCSS plugin. If you also have autoprefixer in your webpack config then make sure that postcss-namespace-selector is called first. This is needed to avoid running the prefixer twice on both standard selectors and vendor specific ones (ex: @keyframes and @webkit-keyframes).

const prefixer = require('postcss-namespace-selector');
 
module: {
  rules: [{
    test: /\.css$/,
    use: [
      require.resolve('style-loader'),
      require.resolve('css-loader'),
      {
        loader: require.resolve('postcss-loader'),
        options: {
          plugins: () => [
            prefixer({
              namespace: '.my-namespace'
            }),
            autoprefixer({
              browsers: ['last 4 versions']
            })
          ]
        }
      }
    ]
  }]
}

Options

• prefix - This string is added before every CSS selector.
• exclude - It's possible to avoid prefixing some selectors by passing an array of selectors (strings or regular expressions).
• transform - In cases where you may want to use the prefix differently for different selectors, it is possible to pass in a custom transform method.
• findConfig - will find the nearest postcss.config.js configuration file when set to true.