找不到模块：无法解析“ReactDOM”答案

【问题标题】：Module not found: Can't resolve 'ReactDOM'找不到模块：无法解析“ReactDOM”
【发布时间】：2018-04-20 11:24:42
【问题描述】：

我有两个 react 项目：

一个 React 组件（使用 webpack 构建）
一个 React 测试项目 (create-react-app)

当将 1 导入 2 编译失败时

Module not found: Can't resolve 'ReactDOM'

组件项目的 Webpack 配置：

var path = require('path');
module.exports = {
  entry: './src/index.tsx',
  output: {
    path: path.resolve(__dirname, 'build'),
    filename: 'index.js'
  },
  devtool: "source-map",
  resolve: {
    extensions: [".ts", ".tsx", ".js", ".json"]
  },
  module: {
    rules: [
      { test: /\.tsx?$/, loader: "awesome-typescript-loader" },
      { test: /(\.css$)/, loaders: ['style-loader', 'css-loader'] },
      { test: /\.(png|woff|woff2|eot|ttf|svg)$/, loader: 'url-loader?limit=100000' },
      { enforce: "pre", test: /\.js$/, loader: "source-map-loader" }
    ]
  },
  externals: {
    'react': 'commonjs react',
    'react-dom': 'ReactDOM'
  }
};

我尝试删除上面的 externals 部分，以便捆绑 ReactDOM，但这似乎也不能解决问题。理想情况下，不需要捆绑 React。 ReactDOM 不是组件项目中的导入。

组件项目的package.json：

{
  "name": "component",
  "version": "0.1.0",
  "main": "build/index.js",
  "dependencies": {
    "react-grid-layout": "^0.16.0",
    "react-redux": "^5.0.6",
    "redux": "^3.7.2",
    "semantic-ui-css": "^2.2.12",
    "semantic-ui-react": "^0.75.1"
  },
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "webpack --watch",
    "build": "webpack"
  },
  "devDependencies": {
    "@types/react": "^16.0.20",
    "@types/react-dom": "^16.0.2",
    "@types/react-grid-layout": "^0.16.0",
    "@types/react-redux": "^5.0.12",
    "awesome-typescript-loader": "^3.3.0",
    "react-dom": "^16.0.0",
    "react": "^16.0.0",
    "babel-cli": "^6.24.1",
    "babel-core": "^6.24.1",
    "babel-loader": "^7.0.0",
    "babel-plugin-transform-object-rest-spread": "^6.23.0",
    "babel-plugin-transform-react-jsx": "^6.24.1",
    "babel-preset-env": "^1.5.1",
    "css-loader": "^0.28.7",
    "file-loader": "^1.1.5",
    "source-map-loader": "^0.2.3",
    "style-loader": "^0.19.0",
    "typescript": "^2.6.1",
    "webpack": "^2.6.1",
    "url-loader": "^0.6.2"
  }
}

在我的测试项目中

import * as React from 'react';    
import * as ReactDOM from 'react-dom';
import Component from 'component'

如果我删除对 Component 的依赖，则测试项目构建良好。一旦我导入组件，完整的错误消息是：

./node_modules/component/build/index.js
Module not found: Can't resolve 'ReactDOM' in '/mnt/c/Users/a8345/ws/test/node_modules/component/build'

当我使用 typescript 时，我安装了 @types/react-dom。如果我有import ReactDOM from 'react-dom'，我会得到./src/index.tsx (2,8): error TS1192: Module '"/mnt/c/Users/a8345/ws/test/node_modules/@types/react-dom/i‌ndex"' has no default export.. import * as ReactDOM from 'react-dom' 在测试项目中工作正常，除非我尝试导入自己的组件。

我怀疑这是一个构建问题而不是导入问题，我应该如何最好地配置它以确保组件使用宿主项目中的 ReactDOM，而不是将其捆绑到组件中？

提前致谢

【问题讨论】：

你的第二个项目中安装了 React 和 ReactDOM 吗？您在package.json 中发布的它们都在devDependencies 中，因此它们可能不会出现在您的第二个项目中。
这为我解决了：stackoverflow.com/a/47722556/15441

标签： javascript reactjs typescript webpack

【解决方案1】：

试试

externals: {
 'react': {commonjs: 'react'},
 'react-dom': {commonjs: 'react-dom'}
}

https://webpack.js.org/configuration/externals/#object

【讨论】：

【解决方案2】：

Webpack 没有解析 .js 文件。将此添加到您的 webpack.config.js。

resolve: {
    extensions: [".ts", ".tsx", ".js", ".jsx"]
},

通过this answer。

【讨论】：