Webpack ReferenceError: require is not defined (ReactJS)

Question

I understand this error happens when the require() function is called in the browser as opposed to within node. However, I can't seem to understand what exactly I need to do to fix this. Any help would be greatly appreciated. You can go to the following repo for whole code base https://github.com/thegreekjester/React_SSR.

Steps to run and reproduce the issue:

• npm install
• npm run dev
• open localhost:3000 in browser
• You will see the error in the console

Webpack.client.js

const path = require('path');
const webpackNodeExternals = require('webpack-node-externals');

module.exports = {

  // production || development
  mode: 'development',

  // Inform webpack that we're building a bundle
  // for nodeJS, rather then for the browser
  target: 'node',

  // Tell webpack the root file of our
  // server application
  entry: './src/client.js',

  // Tell webpack where to put the output file
  // that is generated
  output: {
    filename: 'client_bundle.js',
    path: path.resolve(__dirname, 'build/public'),
    publicPath: '/build/public'
  },
  module: {
    rules: [
      {
        test: /\.js?$/,
        loader: 'babel-loader',
        exclude: '/node_modules/',
        options: {
          presets: [
            'react', 'stage-0', ['env', {
              target: 'web'
            }]
          ]
        }
      }
    ]
  }
};

Webpack.server.js

const path = require('path');
const webpackNodeExternals = require('webpack-node-externals');

module.exports = {

  // production || development
  mode: 'development',

  // Inform webpack that we're building a bundle
  // for nodeJS, rather then for the browser
  target: 'node',

  // Tell webpack the root file of our
  // server application
  entry: './server.js',

  // Tell webpack where to put the output file
  // that is generated
  output: {
    filename: 'bundle.js',
    path: path.resolve(__dirname, 'build'),
    publicPath: '/build'
  },

  module: {
    rules: [
      {
        test: /\.js?$/,
        loader: 'babel-loader',
        exclude: '/node_modules/',
        options: {
          presets: [
            'react', 'stage-0', ['env', {
              target: { browsers: ['last 2 versions']}
            }]
          ]
        }
      }
    ]
  },

  // Tell webpack not to bundle any libraries that exist in the 'node_modules' folder
  // into the server bundle
  externals: [webpackNodeExternals()]

};

Answer 1

In your webpack.client.js, please remove the key target: 'node', because webpack bundling for the client(browser).

In your webpack.server.js, please add a key libraryTarget: 'commonjs2' to output. It would look something like this:

output: {
    filename: 'bundle.js',
    path: path.resolve(__dirname, 'build'),
    publicPath: '/build',
    libraryTarget: 'commonjs2',
},