postcss-focus-within

PostCSS Focus Within

PostCSS Focus Within lets you use the :focus-within pseudo-selector in CSS, following the [Selectors Level 4 specification].

.my-form-field:focus-within label {
  background-color: yellow;
}

/* becomes */

.my-form-field[focus-within] label {
  background-color: yellow;
}

PostCSS Focus Within replaces the :focus-within pseudo-selector with a .focus-within class selector, the same selector used by the focus-within polyfill. The replacement selector can be changed using the replaceWith option.

Usage

Add PostCSS Focus Within to your build tool:

npm install postcss-focus-within --save-dev

Node

Use PostCSS Focus Within to process your CSS:

import focusWithin from 'postcss-focus-within';

focusWithin.process(YOUR_CSS);

PostCSS

Add PostCSS to your build tool:

npm install postcss --save-dev

Use PostCSS Focus Within as a plugin:

import postcss from 'gulp-postcss';
import focusWithin from 'postcss-focus-within';

postcss([
  focusWithin()
]).process(YOUR_CSS);

Webpack

Add PostCSS Loader to your build tool:

npm install postcss-loader --save-dev

Use PostCSS Focus Within in your Gulpfile:

import focusWithin from 'postcss-focus-within';

module.exports = {
  module: {
    rules: [
      {
        test: /\.css$/,
        use: [
          'style-loader',
          { loader: 'css-loader', options: { importLoaders: 1 } },
          { loader: 'postcss-loader', options: {
            ident: 'postcss',
            plugins: () => [ focusWithin() ]
          } }
        ]
      }
    ]
  }
}

Gulp

Add Gulp PostCSS to your build tool:

npm install gulp-postcss --save-dev

Use PostCSS Focus Within in your Gulpfile:

import postcss from 'gulp-postcss';
import focusWithin from 'postcss-focus-within';

gulp.task('css', () => gulp.src('./src/*.css').pipe(
  postcss([
    focusWithin()
  ])
).pipe(
  gulp.dest('.')
));

Grunt

Add Grunt PostCSS to your build tool:

npm install grunt-postcss --save-dev

Use PostCSS Focus Within in your Gruntfile:

import focusWithin from 'postcss-focus-within';

grunt.loadNpmTasks('grunt-postcss');

grunt.initConfig({
  postcss: {
    options: {
      use: [
       focusWithin()
      ]
    },
    dist: {
      src: '*.css'
    }
  }
});

Options

replaceWith

The replaceWith option defines the selector to replace :focus-within. By default, the replacement selector is [focus-within].

focusWithin({ replaceWith: '.focus-within' });

:focus:not(:focus-within) {
  outline: none;
}

/* becomes */

:focus:not(.focus-within]) {
  outline: none;
}