Webpack ReferenceError: require 未定义 (ReactJS)

Question

我了解当在浏览器中调用require()函数而不是在节点内调用时会发生此错误。 但是，我似乎无法理解我到底需要做什么来解决这个问题。 任何帮助将不胜感激。 您可以转到以下存储库获取整个代码库https://github.com/thegreekjester/React_SSR 。

运行和重现问题的步骤：

• 安装
• npm 运行开发
• 在浏览器中打开localhost:3000
• 您将在控制台中看到错误

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

在您的webpack.client.js ，请删除关键target: 'node' ，因为 webpack 捆绑客户端（浏览器）。

在你的webpack.server.js ，请添加一个 key libraryTarget: 'commonjs2'到output 。 它看起来像这样：

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