模块未找到：无法解析“ReactDOM”

Question

我有两个React项目：

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

当在2中导入1时，编译会失败，出现以下错误：

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'
  }
};

我尝试过删除上面的externals部分，以便捆绑ReactDOM，但这似乎也不能解决问题。理想情况下，React不应该需要被捆绑。ReactDOM在组件项目中不是一个导入。

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，我有：

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，测试项目可以正常构建。一旦导入Component，将出现完整的错误消息：

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

我正在使用typescript，并已安装@types/react-dom。如果我有import ReactDOM from 'react-dom'，则会出现错误./src/index.tsx (2,8): error TS1192: Module '"/mnt/c/Users/a8345/ws/test/node_modules/@types/react-dom/i‌​ndex"' has no default export。在测试项目中，import * as ReactDOM from 'react-dom'正常工作，除非我尝试导入自己的组件。

我怀疑这是构建问题而不是导入问题，如何最好地配置以确保组件使用来自主机项目的ReactDOM，而不是将其捆绑到组件中？

提前感谢。

- charns

---

你的第二个项目中是否安装了React和ReactDOM？在你发布的package.json文件中，它们都在devDependencies中，因此可能不会出现在你的第二个项目中。 - kfazi

这个对我解决了问题: https://dev59.com/kVYN5IYBdhLWcg3wQWMV#47722556 - hawkeye

Answer 1

尝试

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

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

- cevek

Answer 2

Webpack无法解析.js文件。在webpack.config.js中添加以下内容。

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

通过这个答案。

- hawkeye