webpack.config.js

const CopyWebpackPlugin = require("copy-webpack-plugin");

const isDevelopment = process.env.NODE_ENV === 'development';

module.exports = {
  mode: process.env.NODE_ENV || "production",
  // エントリーポイントとなるファイル
  entry: {
    index: `${__dirname}/src/index.ts`,
  },
  output: {
    path: `${__dirname}/dist/js`,
    filename: "[name].js",
    clean: true,
  },
  devtool: isDevelopment ? 'eval-cheap-module-source-map' : 'source-map',
  module: {
    rules: [
      {
        test: /\.ts$/,
        use: {
          loader: "ts-loader",
          options: {
            transpileOnly: true,
          },
        },
        exclude: /node_modules/,
      },
    ],
  },
  resolve: {
    // importにて自動解決させる拡張子
    extensions: [".ts", ".js"],
  },
  plugins: [
    new CopyWebpackPlugin({
      patterns: [{ from: "public", to: "../" }],
    }),
  ],
  optimization: {
    minimize: !isDevelopment,
  },
};