postcss.config.js

const path = require( 'path' );

// Check for production mode.
const isProduction = process.env.NODE_ENV === 'production';

// Self hosted fonts path.
const fontsPath = path.join( __dirname, 'assets/fonts' );

// All plugins to use.
const plugins = [

    // Add vendor prefixes to CSS rules.
    require( 'autoprefixer' ),

    // Magically generate all @font-face rules for self hosted fonts.
    require( 'postcss-font-magician' )({
        hosted: [ fontsPath ],
        foundries: [ 'hosted' ]
    }),

    // Pack same CSS media query rules into one.
    require( 'css-mqpacker' )({
        sort: true
    })
];

// Use only for production build.
if ( isProduction ) {

    // Optimize and minify CSS.
    plugins.push(
        require( 'cssnano' )({
            preset: [
                'default',
                {
                    discardComments: {
                        removeAll: true
                    }
                }
            ]
        })
    );
}

module.exports = { plugins };