求助：运行npm run dev时出现Cannot find module 'webpack/bin/config-yargs'错误

我一眼就看出你遇到的核心问题是webpack版本与webpack-dev-server版本不兼容。从你的package.json配置能看到，你装了webpack@4.0.0，但搭配的却是webpack-dev-server@2.11.5——这个版本的dev-server只支持webpack 3及以下版本，而webpack 4对核心模块做了大重构，把webpack/bin/config-yargs相关功能移到了webpack-cli里，旧版本的dev-server找不到这个模块，自然就报错了。

下面给你具体的解决步骤：

步骤1：升级webpack-dev-server到兼容webpack 4的版本 #

先卸载当前的旧版本dev-server：

npm uninstall webpack-dev-server --save-dev

然后安装支持webpack 4的3.x版本（我推荐3.11.2，稳定性不错）：

npm install webpack-dev-server@^3.11.2 --save-dev

步骤2：（可选）清理依赖重新安装 #

如果升级后还是有奇怪问题，可以试试彻底清理现有依赖再重装：

Windows系统： #

rmdir /s /q node_modules
del package-lock.json
npm install

macOS/Linux系统： #

rm -rf node_modules package-lock.json
npm install

为什么这个方法有效？ #

webpack 4.x重构时移除了webpack/bin/config-yargs模块，把相关功能整合到了webpack-cli中。而webpack-dev-server@2.x的源码里依然直接引用这个旧模块路径，导致找不到文件报错。升级到webpack-dev-server@3.x之后，它已经适配了webpack 4的模块结构，会正确从webpack-cli中获取所需功能。

另外检查你的package.json，已经正确安装了webpack-cli，这是webpack 4运行必须的依赖，所以这部分不用额外调整。

你的命令行错误输出： #

C:\Users\ASUS\Desktop\truffle-webpack-ipfs-bootstrap-master\truffle-webpack-ipfs-bootstrap-master>npm run dev
> truffle-init-webpack@0.0.2 dev C:\Users\ASUS\Desktop\truffle-webpack-ipfs-bootstrap-master\truffle-webpack-ipfs-bootstrap-master
> webpack-dev-server
internal/modules/cjs/loader.js:613
throw err;
^
Error: Cannot find module 'webpack/bin/config-yargs'
Require stack:
- C:\Users\ASUS\Desktop\truffle-webpack-ipfs-bootstrap-master\truffle-webpack-ipfs-bootstrap-master\node_modules\webpack-dev-server\bin\webpack-dev-server.js
at Function.Module._resolveFilename (internal/modules/cjs/loader.js:610:15)
at Function.Module._load (internal/modules/cjs/loader.js:526:27)
at Module.require (internal/modules/cjs/loader.js:666:19)
at require (internal/modules/cjs/helpers.js:16:16)
at Object.<anonymous> (C:\Users\ASUS\Desktop\truffle-webpack-ipfs-bootstrap-master\truffle-webpack-ipfs-bootstrap-master\node_modules\webpack-dev-server\bin\webpack-dev-server.js:54:1)
at Module._compile (internal/modules/cjs/loader.js:759:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:770:10)
at Module.load (internal/modules/cjs/loader.js:628:32)
at Function.Module._load (internal/modules/cjs/loader.js:555:12)
at Function.Module.runMain (internal/modules/cjs/loader.js:824:10)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! truffle-init-webpack@0.0.2 dev: `webpack-dev-server`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the truffle-init-webpack@0.0.2 dev script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR! C:\Users\ASUS\AppData\Roaming\npm-cache\_logs\2019-08-30T09_10_59_739Z-debug.log

你的package.json配置： #

{
  "name": "truffle-init-webpack",
  "version": "0.0.2",
  "description": "Frontend example using truffle v3",
  "scripts": {
    "lint": "eslint ./",
    "build": "webpack",
    "dev": "webpack-dev-server"
  },
  "author": "Douglas von Kohorn",
  "license": "MIT",
  "devDependencies": {
    "babel-cli": "^6.22.2",
    "babel-core": "^6.26.3",
    "babel-eslint": "^6.1.2",
    "babel-loader": "^6.2.10",
    "babel-plugin-transform-runtime": "^6.22.0",
    "babel-preset-env": "^1.7.0",
    "babel-preset-es2015": "^6.22.0",
    "babel-register": "^6.22.0",
    "copy-webpack-plugin": "^4.6.0",
    "css-loader": "^3.2.0",
    "eslint": "^3.14.0",
    "eslint-config-standard": "^6.0.0",
    "eslint-plugin-babel": "^4.0.0",
    "eslint-plugin-mocha": "^4.8.0",
    "eslint-plugin-promise": "^3.8.0",
    "eslint-plugin-standard": "^2.0.0",
    "html-webpack-plugin": "^2.28.0",
    "json-loader": "^0.5.4",
    "style-loader": "^0.13.1",
    "truffle-contract": "^1.1.11",
    "web3": "^0.20.7",
    "webpack": "^4.0.0",
    "webpack-cli": "^3.3.7",
    "webpack-dev-server": "^2.11.5"
  },
  "dependencies": {
    "ajv": "^5.5.2",
    "boostrap": "^2.0.0",
    "bootstrap": "^4.3.1",
    "ipfs-api": "^19.0.0",
    "jquery": "^3.4.1",
    "node-sass": "^4.8.3",
    "popper.js": "^1.15.0",
    "postcss-loader": "^2.1.6",
    "precss": "^3.1.2",
    "sass-loader": "^6.0.7"
  }
}

内容的提问来源于stack exchange，提问作者Jessie