laravel webpack mix config

webpack.mix.js

const mix = require('laravel-mix');

require('laravel-mix-polyfill');

/*
 |--------------------------------------------------------------------------
 | 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/js/app.js', 'public/js')
.sass('resources/sass/app.sass', 'public/css')
    .options({
       autoprefixer: {
           options: {
                overrideBrowserslist: ['last 20 versions'],
                cascade: false
           }
       }
    })
    .polyfill({
        enabled: true,
        useBuiltIns: "usage",
        targets: {"firefox": "50", "ie": 11}
     });

// or

mix.sass('resources/sass/app.sass', 'public/css').options({
    postCss: [
        require('autoprefixer')({
            browsers: [
                'last 20 versions',
                'iOS >= 8',
                'Safari >= 8',
            ],
            cascade: false,
            flexbox: "no-2009"
        }),
    ]
});