Laravel Mix + Tailwind CSS + PurgeCss

packages.json

{
    "private": true,
    "scripts": {
        "dev": "npm run development",
        "development": "cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js",
        "watch": "cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --watch --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js",
        "watch-poll": "npm run watch -- --watch-poll",
        "hot": "cross-env NODE_ENV=development node_modules/webpack-dev-server/bin/webpack-dev-server.js --inline --hot --config=node_modules/laravel-mix/setup/webpack.config.js",
        "prod": "npm run production",
        "production": "cross-env NODE_ENV=production node_modules/webpack/bin/webpack.js --no-progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js"
    },
    "devDependencies": {
        "axios": "^0.17",
        "cross-env": "^5.1",
        "laravel-mix": "^2.0",
        "laravel-mix-purgecss": "^1.0",
        "less": "^2.7.3",
        "less-loader": "^4.0.5",
        "lodash": "^4.17.4",
        "tailwindcss": "^0.4",
        "vue": "^2.5.7"
    }
}

webpack.mix.js

let mix = require('laravel-mix');
let tailwindcss = require('tailwindcss');

require('laravel-mix-purgecss');

/*
 |--------------------------------------------------------------------------
 | Mix Asset Management
 |--------------------------------------------------------------------------
 |
 | Mix provides a clean, fluent API for defining some Webpack build steps
 | for your Laravel application. By default, we are compiling the Sass
 | file for the application as well as bundling up all the JS files.
 |
 */

mix.js('resources/assets/js/app.js', 'public/js')
   .less('resources/assets/less/app.less', 'public/css')
   .options({
         postCss: [
             tailwindcss('tailwind.js'),
         ]
     });

if (mix.inProduction()) {
    mix.purgeCss()
       .version();
}