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Discussion on: 0cjs! Webpack4 tutorial: Building React app without config file.

shisama profile image
Masashi Hirano Author • Edited on

Sorry to reply late.
If your webpack.config.js doesn't have 'mode' property, you have to add 'mode' property into your webpack.config.js.

The below is an example.

module.exports = {
  mode: 'production', // <= It is necessary to resolve the warning
  entry: {
    'index': [
      path.resolve(__dirname, 'src/index.js')
  output: {
    filename: '[name].js',
    path: path.resolve(__dirname, 'public'),
    publicPath: '/',
  plugins: [
    new webpack.DefinePlugin({
      'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV)
  module: {
    rules: [
        test: /\.(js|jsx)$/,
        use: 'babel-loader',
  resolve: {
    extensions: ['.js', '.jsx'],

Thank you for reading this post.

evgenyx82 profile image

Hello, Masashi Hirano.

It's seems im miss something in the past, here is examples )

Anyway, thx ) for response.