反应构建问题，。/ src / index.js中的ERROR模块构建失败（来自./node_modules/babel-loader/lib/index.js）：

Question

我正在尝试使用Webpack 4从头开始构建反应应用程序

我尝试构建时遇到以下错误。虽然已经安装了babel-core，但我也尝试安装@ babel / core但它没有用

ERROR in ./src/index.js
Module build failed (from ./node_modules/babel-loader/lib/index.js):
Error: Cannot find module '@babel/core'
    at Function.Module._resolveFilename (module.js:538:15)
    at Function.Module._load (module.js:468:25)
    at Module.require (module.js:587:17)
    at require (internal/module.js:11:18)
    at Object.<anonymous> (/Users/digvijay.upadhyay/digvijayu/react_webpack_4_from_scratch/node_modules/babel-loader/lib/index.js:5:15)
    at Module._compile (module.js:643:30)
    at Object.Module._extensions..js (module.js:654:10)
    at Module.load (module.js:556:32)
    at tryModuleLoad (module.js:499:12)
    at Function.Module._load (module.js:491:3)
 @ multi (webpack)-dev-server/client?http://localhost:8080 ./src main[1]
Child html-webpack-plugin for "index.html":
     1 asset
    Entrypoint undefined = ./index.html
    [./node_modules/html-webpack-plugin/lib/loader.js!./src/index.html] 500 bytes {0} [built]
    [./node_modules/lodash/lodash.js] 527 KiB {0} [built]
    [./node_modules/webpack/buildin/global.js] (webpack)/buildin/global.js 489 bytes {0} [built]
    [./node_modules/webpack/buildin/module.js] (webpack)/buildin/module.js 497 bytes {0} [built]
ℹ ｢wdm｣: Failed to compile.

webpack.config.js

const HtmlWebPackPlugin = require("html-webpack-plugin");

const htmlPlugin = new HtmlWebPackPlugin({
  template: "./src/index.html",
  filename: "./index.html"
});

module.exports = {
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: {
          loader: "babel-loader"
        }
      }
    ]
  },
  plugins: [htmlPlugin]
};

编辑：将包json文件添加到问题package.json

"devDependencies": {
    "babel-core": "^6.26.3",
    "babel-loader": "^8.0.0",
    "babel-preset-env": "^1.7.0",
    "babel-preset-react": "^6.24.1",
    "html-webpack-plugin": "^3.2.0",
    "webpack": "^4.17.1",
    "webpack-cli": "^3.1.0",
    "webpack-dev-server": "^3.1.6"
  },
  "dependencies": {
    "@babel/core": "^7.0.0",
    "path": "^0.12.7",
    "react": "^16.4.2",
    "react-dom": "^16.4.2"
  }

{“name”：“boiler-plate-react-webpack-4”，“main”：“index.js”，“scripts”：{“start”：“webpack-dev-server --mode development --open - -display-error-details“，”build-dev“：”webpack --mode development“，”build-prod“：”webpack --mode production“，”test“：”echo“错误：没有指定测试\ “&& exit 1”}，“devDependencies”：{“babel-core”：“^ 6.26.3”，“babel-loader”：“^ 8.0.0”，“babel-preset-env”：“^ 1.7。 0“，”babel-preset-react“：”^ 6.24.1“，”html-webpack-plugin“：”^ 3.2.0“，”webpack“：”^ 4.17.1“，”webpack-cli“： “^ 3.1.0”，“webpack-dev-server”：“^ 3.1.6”}，“依赖项”：{“@ babel / core”：“^ 7.0.0”，“path”：“^ 0.12。 7“，”反应“：”^ 16.4.2“，”react-dom“：”^ 16.4.2“}}

Answer 1

解决了：

问题是包babel-loader，最新版本预计@ babel / core。将版本降级为7.x，现在很好

"devDependencies": {
    "babel-core": "^6.26.3",
    "babel-loader": "^7.1.5",
    "babel-preset-env": "^1.7.0",
    "babel-preset-react": "^6.24.1",
    "html-webpack-plugin": "^3.2.0",
    "webpack": "^4.17.1",
    "webpack-cli": "^3.1.0",
    "webpack-dev-server": "^3.1.6"
  },
  "dependencies": {
    "react": "^16.4.2",
    "react-dom": "^16.4.2"
  }

Answer 2

是的，babel-loader 8需要babel 7，令人困惑。如果你想使用新的babel，它非常简单。你会做这样的事情：

"devDependencies": {
    "babel-loader": "^8.0.0",
    "@babel/core": "^7.0.0",
    "@babel/preset-env": "^7.0.0",
    "@babel/preset-react": "^7.0.0",,
    "html-webpack-plugin": "^3.2.0",
    "webpack": "^4.17.1",
    "webpack-cli": "^3.1.0",
    "webpack-dev-server": "^3.1.6"
  },
  "dependencies": {
    "react": "^16.4.2",
    "react-dom": "^16.4.2"
  }

除了您定义它们之外，还可以对您的babel预设进行一些小改动：

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

您可以在这里看到我更新为babel 7的项目的差异：https://github.com/ccnmtl/astro-interactives/commit/97b31ca7948d177d7f41439bdbeb0a54cd3e69da

Answer 3

另一种解决方法是保持@babel/core并安装babel-core : ^7.0.0-bridge.0。它是一个桥接软件包，允许您支持以前的babel软件包并将您的babel核心更新到最新版本。然后你也可以将你的babel-loader更新为LTS。