webpack.config.js

const { resolve } = require("path");

const { BannerPlugin, EnvironmentPlugin } = require("webpack");

const merge = require("webpack-merge");
const {
  argv: { mode }
} = require("yargs");
const camelcase = require("camelcase");

const { name: filename } = require("./package.json");

const banner = String.prototype.trim.call(`
Copyright (c) 2018 Florian Klampfer <https://qwtel.com/>

This source code is licensed under the MIT license found in the
LICENSE file in the root directory of this source tree.
`);
const library = camelcase(filename);
const min = mode === "production" ? ".min" : "";

function envConfig() {
  switch (mode) {
    case "production":
      return {
        plugins: [
          new BannerPlugin({ banner }),
          new EnvironmentPlugin({ DEBUG: false })
        ]
      };

    default:
      return {
        devtool: "source-map",
        plugins: [new EnvironmentPlugin({ DEBUG: true })]
      };
  }
}

const baseConfig = merge(
  {
    output: {
      path: resolve("./dist"),
      library,
      libraryTarget: "umd",
      umdNamedDefine: true
    },
    module: {
      rules: [
        {
          test: /(\.jsx|\.js)$/,
          loader: "babel-loader"
        }
      ]
    },
    externals: {
      rxjs: {
        commonjs: "rxjs",
        commonjs2: "rxjs",
        amd: "rxjs",
        root: "Rx"
      }
    },
    resolve: {
      modules: [resolve("./node_modules")],
      extensions: [".json", ".js"]
    }
  },
  envConfig()
);

const config = [
  merge(baseConfig, {
    entry: resolve("./index.js"),
    output: {
      filename: `index${min}.js`
    }
  })
];

module.exports = config;