React安装中出现错误怎么办

Question

我正在尝试安装react，但在进行npm启动时遇到了一个错误，我已经尝试了很多关于改变babel版本的解决方案，但仍然无法完全解决它。

错误。

C:\Users\support\Desktop\reactApp>npm start

> [email protected] start C:\Users\support\Desktop\reactApp
> webpack-dev-server --mode development --open --hot

i ｢wds｣: Project is running at http://localhost:8001/
i ｢wds｣: webpack output is served from /
i ｢wds｣: Content not from webpack is served from C:\Users\support\Desktop\reactApp
i ｢wdm｣: wait until bundle finished: /
× ｢wdm｣: Hash: 8012f13b5074e55019d9
Version: webpack 4.43.0
Time: 645ms
Built at: 06/02/2020 2:29:04 PM
          Asset       Size  Chunks             Chunk Names
     index.html  272 bytes          [emitted]
index_bundle.js    395 KiB    main  [emitted]  main
Entrypoint main = index_bundle.js
[0] multi (webpack)-dev-server/client?http://localhost:8001 (webpack)/hot/dev-server.js ./main.js 52 bytes {main} [built]
[./main.js] 1.37 KiB {main} [built] [failed] [1 error]
[./node_modules/webpack-dev-server/client/index.js?http://localhost:8001] (webpack)-dev-server/client?http://localhost:8001 4.29 KiB {main} [built]
[./node_modules/webpack-dev-server/client/overlay.js] (webpack)-dev-server/client/overlay.js 3.51 KiB {main} [built]
[./node_modules/webpack-dev-server/client/socket.js] (webpack)-dev-server/client/socket.js 1.53 KiB {main} [built]
[./node_modules/webpack-dev-server/client/utils/createSocketUrl.js] (webpack)-dev-server/client/utils/createSocketUrl.js 2.91 KiB {main} [built]
[./node_modules/webpack-dev-server/client/utils/log.js] (webpack)-dev-server/client/utils/log.js 964 bytes {main} [built]
[./node_modules/webpack-dev-server/client/utils/reloadApp.js] (webpack)-dev-server/client/utils/reloadApp.js 1.59 KiB {main} [built]
[./node_modules/webpack-dev-server/client/utils/sendMessage.js] (webpack)-dev-server/client/utils/sendMessage.js 402 bytes {main} [built]
[./node_modules/webpack-dev-server/node_modules/strip-ansi/index.js] (webpack)-dev-server/node_modules/strip-ansi/index.js 161 bytes {main} [built]
[./node_modules/webpack/hot sync ^\.\/log$] (webpack)/hot sync nonrecursive ^\.\/log$ 170 bytes {main} [built]
[./node_modules/webpack/hot/dev-server.js] (webpack)/hot/dev-server.js 1.59 KiB {main} [built]
[./node_modules/webpack/hot/emitter.js] (webpack)/hot/emitter.js 75 bytes {main} [built]
[./node_modules/webpack/hot/log-apply-result.js] (webpack)/hot/log-apply-result.js 1.27 KiB {main} [built]
[./node_modules/webpack/hot/log.js] (webpack)/hot/log.js 1.34 KiB {main} [built]
    + 20 hidden modules

ERROR in ./main.js
Module build failed (from ./node_modules/babel-loader/lib/index.js):
Error: Cannot find module 'babel-preset-env' from 'C:\Users\support\Desktop\reactApp'
- Did you mean "@babel/env"?
    at Function.resolveSync [as sync] (C:\Users\support\Desktop\reactApp\node_modules\resolve\lib\sync.js:89:15)
    at resolveStandardizedName (C:\Users\support\Desktop\reactApp\node_modules\@babel\core\lib\config\files\plugins.js:101:31)
    at resolvePreset (C:\Users\support\Desktop\reactApp\node_modules\@babel\core\lib\config\files\plugins.js:58:10)
    at loadPreset (C:\Users\support\Desktop\reactApp\node_modules\@babel\core\lib\config\files\plugins.js:77:20)
    at createDescriptor (C:\Users\support\Desktop\reactApp\node_modules\@babel\core\lib\config\config-descriptors.js:154:9)
    at C:\Users\support\Desktop\reactApp\node_modules\@babel\core\lib\config\config-descriptors.js:109:50
    at Array.map (<anonymous>)
    at createDescriptors (C:\Users\support\Desktop\reactApp\node_modules\@babel\core\lib\config\config-descriptors.js:109:29)
    at createPresetDescriptors (C:\Users\support\Desktop\reactApp\node_modules\@babel\core\lib\config\config-descriptors.js:101:10)
    at C:\Users\support\Desktop\reactApp\node_modules\@babel\core\lib\config\config-descriptors.js:58:104
Child HtmlWebpackCompiler:
     1 asset
    Entrypoint HtmlWebpackPlugin_0 = __child-HtmlWebpackPlugin_0
    [./node_modules/html-webpack-plugin/lib/loader.js!./index.html] 501 bytes {HtmlWebpackPlugin_0} [built]
i ｢wdm｣: Failed to compile.

这些是我的以下文件

webpack.comfig.js

const path = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');

module.exports = {
   entry: './main.js',
   output: {
      path: path.join(__dirname, '/bundle'),
      filename: 'index_bundle.js'
   },
   devServer: {
      inline: true,
      port: 8001
   },
   module: {
      rules: [
         {
            test: /\.jsx?$/,
            exclude: /node_modules/,
            loader: 'babel-loader',
            query: {
               presets: ['env', 'react']
            }
         }
      ]
   },
   plugins:[
      new HtmlWebpackPlugin({
         template: './index.html'
      })
   ]
}

webpack.comfig.js

{
  "name": "reactapp",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "start": "webpack-dev-server --mode development --open --hot",
    "build": "webpack --mode production"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "react": "^16.13.1",
    "react-dom": "^16.13.1",
    "webpack": "^4.43.0",
    "webpack-cli": "^3.3.11",
    "webpack-dev-server": "^3.11.0"
  },
  "devDependencies": {
    "@babel/core": "^7.10.2",
    "@babel/preset-env": "^7.10.2",
    "@babel/preset-react": "^7.10.1",
    "babel-loader": "^8.1.0",
    "html-webpack-plugin": "^4.3.0"
  }
}

.babelrc

{
    "presets": [
        "@babel/preset-env",
        "@babel/preset-react"
    ]
}

Answer 1

您正在使用babel预设7+。

在您的webpack.config.js中这样做。

presets: ['@babel/preset-env']

Answer 2

在webpack.config中 - 不要认为你需要下面的内容，因为你的babelrc文件已经涵盖了这一点。尝试从webpack中删除它。

        query: {
           presets: ['env', 'react']
        }