webpack.config.js

// Template for webpack.config.js in Fable projects
// Find latest version in https://github.com/fable-compiler/webpack-config-template

// In most cases, you'll only need to edit the CONFIG object
// See below if you need better fine-tuning of Webpack options

var CONFIG = {
    indexHtmlTemplate: "./src/index.html",
    fsharpEntry: "./src/App.fsproj",
    cssEntry: "./src/style.sass",
    outputDir: "./deploy",
    assetsDir: "./public",
    devServerPort: 8080,
    devServerProxy: undefined,
    // Use babel-preset-env to generate JS compatible with most-used browsers.
    // More info at https://github.com/babel/babel/blob/master/packages/babel-preset-env/README.md
    babel: {
        presets: [
            ["env", {
                "modules": false,
                "useBuiltIns": "usage",
            }]
        ],
    }
}

// If we're running the webpack-dev-server, assume we're in development mode
var isProduction = !process.argv.find(v => v.indexOf('webpack-dev-server') !== -1);
console.log("Bundling for " + (isProduction ? "production" : "development") + "...");

var path = require("path");
var webpack = require("webpack");
var HtmlWebpackPlugin = require('html-webpack-plugin');
var CopyWebpackPlugin = require('copy-webpack-plugin');
var MiniCssExtractPlugin = require("mini-css-extract-plugin");
var UglifyJSPlugin = require('uglifyjs-webpack-plugin');

// The HtmlWebpackPlugin allows us to use a template for the index.html page
// and automatically injects <script> or <link> tags for generated bundles.
var commonPlugins = [
    new HtmlWebpackPlugin({
        filename: 'index.html',
        template: CONFIG.indexHtmlTemplate
    })
];

module.exports = {
    entry: CONFIG.fsharpEntry,
    // NOTE we add a hash to the output file name in production
    // to prevent browser caching if code changes
    output: {
        path: path.join(__dirname, CONFIG.outputDir),
        filename: isProduction ? '[name].[hash].js' : '[name].js'
    },
    mode: isProduction ? "production" : "development",
    devtool: isProduction ? "source-map" : "eval-source-map",
    optimization: {
        // Split the code coming from npm packages into a different file.
        // 3rd party dependencies change less often, let the browser cache them.
        splitChunks: {
            cacheGroups: {
                commons: {
                    test: /node_modules/,
                    name: "vendors",
                    chunks: "all"
                }
            }
        },
    },
    // Besides the HtmlPlugin, we use the following plugins:
    // PRODUCTION
    //      - MiniCssExtractPlugin: Extracts CSS from bundle to a different file
    //      - CopyWebpackPlugin: Copies static assets to output directory
    // DEVELOPMENT
    //      - HotModuleReplacementPlugin: Enables hot reloading when code changes without refreshing
    plugins: isProduction ?
        commonPlugins.concat([
            new MiniCssExtractPlugin({ filename: 'style.css' }),
            new CopyWebpackPlugin([{ from: CONFIG.assetsDir }]),
            // Inlining is causing problems in minified code
            // See https://github.com/mishoo/UglifyJS2/issues/2842#issuecomment-359527962
            new UglifyJSPlugin({
                uglifyOptions: {
                    compress: { inline: false }
                }
            }),
        ])
        : commonPlugins.concat([
            new webpack.HotModuleReplacementPlugin(),
        ]),
    // Configuration for webpack-dev-server
    devServer: {
        publicPath: "/",
        contentBase: CONFIG.assetsDir,
        port: CONFIG.devServerPort,
        proxy: CONFIG.devServerProxy,
        hot: true,
        inline: true
    },
    // - fable-loader: transforms F# into JS
    // - babel-loader: transforms JS to old syntax (compatible with old browsers)
    // - sass-loaders: transforms SASS/SCSS into JS
    // - file-loader: Moves files referenced in the code (fonts, images) into output folder
    module: {
        rules: [
            {
                test: /\.fs(x|proj)?$/,
                use: "fable-loader"
            },
            {
                test: /\.js$/,
                exclude: /node_modules/,
                use: {
                    loader: 'babel-loader',
                    options: CONFIG.babel
                },
            },
            {
                test: /\.(sass|scss|css)$/,
                use: [
                    isProduction ? MiniCssExtractPlugin.loader :
                        'style-loader',
                    'css-loader',
                    'sass-loader',
                ],
            },
            {
                test: /\.(png|jpg|jpeg|gif|svg|woff|woff2|ttf|eot)(\?.*)?$/,
                use: ["file-loader"]
            }
        ]
    }
};