webpack.config.js

// https://webpack.js.org/configuration
const webpack = require("webpack"),
  path = require("path"),
  prod = process.env.NODE_ENV === "production",
  // The output directory for all build artifacts. Only absolute paths are accepted by
  // output.path.
  distDir = path.resolve(__dirname, process.env.BUILD_DIR || "static/build/js");

module.exports = {
  // Fail on the first build error instead of tolerating it for prod builds. This seems to
  // correspond to optimization.noEmitOnErrors.
  bail: prod,

  // Specify that all paths are relative the Webpack configuration directory not the current
  // working directory.
  context: __dirname,

  // A map of ResourceLoader module / entry chunk names to JavaScript files to pack.
  entry: {
    all: "./openlibrary/plugins/openlibrary/js/index.js",
    partnerLib: "./openlibrary/plugins/openlibrary/js/partner_ol_lib.js",
    sw: "./openlibrary/plugins/openlibrary/js/service-worker.js",
  },

  resolve: {
    alias: {},
  },
  plugins: [
    new webpack.ProvidePlugin({
      $: "jquery",
      jQuery: "jquery",
    }),
  ],
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: {
          loader: "babel-loader",
          options: {
            // Beware of https://github.com/babel/babel-loader/issues/690.
            // Changes to browsers require manual invalidation.
            cacheDirectory: true,
          },
        },
      },
      {
        test: /\.css$/,
        use: [
          {
            loader: "style-loader",
          },
          {
            loader: "css-loader",
            options: {
              url: false,
            },
          },
        ],
      },
    ],
  },
  optimization: {
    splitChunks: {
      cacheGroups: {
        // Turn off webpack's default 'vendors' cache group. If this is desired
        // later on, we can explicitly turn this on for clarity.
        // https://webpack.js.org/plugins/split-chunks-plugin/#optimization-splitchunks
        vendors: false,
      },
    },
    // Don't produce production output when a build error occurs.
    emitOnErrors: !prod,
  },

  output: {
    // Specify the destination of all build products.
    path: distDir,
    // base path for build products when referenced from production
    // (see https://webpack.js.org/guides/public-path/)
    publicPath: "/static/build/js/",

    // Store outputs per module in files named after the modules. For the JavaScript entry
    // itself, append .js to each ResourceLoader module entry name.
    filename: "[name].js",

    // This option determines the name of **non-entry** chunk files.
    chunkFilename: "[name].[contenthash].js",
  },

  // Accurate source maps at the expense of build time.
  // The source map is intentionally exposed
  // to users via sourceMapFilename for prod debugging.
  devtool: "source-map",
  mode: prod ? "production" : "development",

  performance: {
    maxAssetSize: 703 * 1024,
    maxEntrypointSize: 703 * 1024,
    // Size violations for prod builds fail; development builds are unchecked.
    hints: prod ? "error" : false,
  },

  // Useful for developing in docker/windows, which doesn't support file watchers
  watchOptions:
    process.env.FORCE_POLLING === "true"
      ? {
          poll: 1000, // Check for changes every second
          aggregateTimeout: 300, // Delay before rebuilding
          ignored: /node_modules/,
        }
      : undefined,
};