How to use the laravel-mix.config.inProduction function in laravel-mix

new webpackPlugins.WebpackChunkHashPlugin()
    );
}

if (Mix.options.purifyCss) {
    let PurifyCSSPlugin = require('purifycss-webpack');

    // By default, we'll scan all Blade and Vue files in our project.
    let paths = glob.sync(Mix.Paths.root('resources/views/**/*.blade.php')).concat(
        Mix.entry().scripts.reduce((carry, js) => {
            return carry.concat(glob.sync(js.base + '/**/*.vue'));
        }, [])
    );

    plugins.push(new PurifyCSSPlugin(
        Object.assign({paths}, Mix.options.purifyCss, {minimize : Mix.inProduction})
    ));
}

if (Mix.inProduction && Mix.options.uglify) {
    plugins.push(
        new webpack.optimize.UglifyJsPlugin(Mix.options.uglify)
    );
}

plugins.push(
    new webpack.DefinePlugin(
        Mix.definitions({
            NODE_ENV : Mix.inProduction
                ? 'production'
                : ( process.env.NODE_ENV || 'development' )
        })

new webpackPlugins.WebpackChunkHashPlugin()
    );
}

if (Mix.options.purifyCss) {
    let PurifyCSSPlugin = require('purifycss-webpack');

    // By default, we'll scan all Blade and Vue files in our project.
    let paths = glob.sync(Mix.Paths.root('resources/views/**/*.blade.php')).concat(
        Mix.js.reduce((carry, js) => {
            return carry.concat(glob.sync(js.entry.map(entry => entry.base) + '/**/*.vue'));
        }, [])
    );

    plugins.push(new PurifyCSSPlugin(
        Object.assign({ paths }, Mix.options.purifyCss, { minimize: Mix.inProduction })
    ));
}

if (Mix.inProduction) {
    plugins.push(
        new webpack.DefinePlugin({
            'process.env': {
                NODE_ENV: '"production"'
            }
        }),

        new webpack.optimize.UglifyJsPlugin(Mix.options.uglify)
    );
}

plugins.push(

//         jQuery: 'jquery',
    //         $: 'jquery',
    //         jquery: 'jquery'
    //     }),

    new plugins.FriendlyErrorsWebpackPlugin(),

    new plugins.StatsWriterPlugin({
        filename: 'mix-manifest.json',
        transform: Mix.manifest.transform.bind(Mix.manifest),
    }),

    new plugins.WebpackMd5HashPlugin(),

    new webpack.LoaderOptionsPlugin({
        minimize: Mix.inProduction,
        options: {
            postcss: Mix.options.postCss,
            context: __dirname,
            output: { path: './' }
        }
    })
]);


if (Mix.browserSync) {
    module.exports.plugins.push(
        new plugins.BrowserSyncPlugin(
            Object.assign({
                host: 'localhost',
                port: 3000,
                proxy: 'app.dev',

//         $: 'jquery',
    //         jquery: 'jquery',
    //         'window.jQuery': 'jquery'
    //     }),

    new plugins.FriendlyErrorsWebpackPlugin(),

    new plugins.StatsWriterPlugin({
        filename: 'mix-manifest.json',
        transform: Mix.manifest.transform.bind(Mix.manifest),
    }),

    new plugins.WebpackMd5HashPlugin(),

    new webpack.LoaderOptionsPlugin({
        minimize: Mix.inProduction,
        options: {
            postcss: [
                require('autoprefixer')
            ],
            context: __dirname,
            output: { path: './' }
        }
    })
]);


if (Mix.notifications) {
    module.exports.plugins.push(
        new plugins.WebpackNotifierPlugin({
            title: 'Laravel Mix',
            alwaysNotify: true,

$: 'jquery',
        jquery: 'jquery',
        'window.jQuery': 'jquery'
    }),

    new plugins.FriendlyErrorsWebpackPlugin(),

    // new plugins.StatsWriterPlugin({
    //     filename: 'mix-manifest.json',
    //     transform: Mix.manifest.transform.bind(Mix.manifest),
    // }),

    new plugins.WebpackMd5HashPlugin(),

    new webpack.LoaderOptionsPlugin({
        minimize: Mix.inProduction,
        options: {
            postcss: [
                require('autoprefixer')
            ],
            context: __dirname,
            output: { path: './' }
        }
    })
]);


if (Mix.notifications) {
    module.exports.plugins.push(
        new plugins.WebpackNotifierPlugin({
            title: 'Laravel Mix',
            alwaysNotify: true,

| extensions, for versioning, OS notifications, and much more.
 |
 */

plugins.push(
    new webpack.ProvidePlugin(Mix.autoload || {}),

    new webpackPlugins.FriendlyErrorsWebpackPlugin({ clearConsole: Mix.options.clearConsole }),

    new webpackPlugins.StatsWriterPlugin({
        filename: 'mix-manifest.json',
        transform: Mix.manifest.transform.bind(Mix.manifest),
    }),

    new webpack.LoaderOptionsPlugin({
        minimize: Mix.inProduction,
        options: {
            postcss: Mix.options.postCss,
            context: __dirname,
            output: { path: './' }
        }
    })
);

if (Mix.browserSync) {
    plugins.push(
        new webpackPlugins.BrowserSyncPlugin(
            Object.assign({
                host: 'localhost',
                port: 3000,
                proxy: 'app.dev',
                files: [

}


if (Mix.extract) {
    module.exports.plugins.push(
        new webpack.optimize.CommonsChunkPlugin({
            names: Mix.entryBuilder.extractions.concat([
                path.join(Mix.js.base, 'manifest')
            ]),
            minChunks: Infinity
        })
    );
}


if (Mix.inProduction) {
    module.exports.plugins = module.exports.plugins.concat([
        new webpack.DefinePlugin({
            'process.env': {
                NODE_ENV: '"production"'
            }
        }),

        /*
        new webpack.optimize.UglifyJsPlugin({
            sourceMap: true,
            compress: {
                warnings: false,
                drop_console: true
            }
        })
        */

plugins.push(new PurifyCSSPlugin(
        Object.assign({ paths }, Mix.options.purifyCss, { minimize: Mix.inProduction })
    ));
}

if (Mix.inProduction && Mix.options.uglify) {
    plugins.push(
        new webpack.optimize.UglifyJsPlugin(Mix.options.uglify)
    );
}

plugins.push(
    new webpack.DefinePlugin(
        Mix.definitions({
            NODE_ENV: Mix.inProduction
                ? 'production'
                : ( process.env.NODE_ENV || 'development' )
        })
    ),

    new webpackPlugins.WebpackOnBuildPlugin(
        stats => global.events.fire('build', stats)
    )
);

if (! Mix.entry().hasScripts()) {
    plugins.push(new webpackPlugins.MockEntryPlugin(Mix.output().path));
}

module.exports.plugins = plugins;

let path              = require('path');
let glob              = require('glob');
let webpack           = require('webpack');
let Mix               = require('laravel-mix').config;
let webpackPlugins    = require('laravel-mix').plugins;
let SmartBannerPlugin = require('smart-banner-webpack-plugin');
let min               = Mix.inProduction ? '.min' : '';

/*
 |--------------------------------------------------------------------------
 | Mix Initialization
 |--------------------------------------------------------------------------
 |
 | As our first step, we'll require the project's Laravel Mix file
 | and record the user's requested compilation and build steps.
 | Once those steps have been recorded, we may get to work.
 |
 */

Mix.initialize();

/*
 |--------------------------------------------------------------------------

}


if (Mix.extract) {
    module.exports.plugins.push(
        new webpack.optimize.CommonsChunkPlugin({
            names: Mix.entryBuilder.extractions.concat([
                path.join(Mix.js.base, 'manifest')
            ]),
            minChunks: Infinity
        })
    );
}


if (Mix.inProduction) {
    module.exports.plugins = module.exports.plugins.concat([
        new webpack.DefinePlugin({
            'process.env': {
                NODE_ENV: '"production"'
            }
        }),

        new webpack.optimize.UglifyJsPlugin({
            sourceMap: true,
            compress: {
                warnings: false,
                drop_console: true
            }
        })
    ]);
}