转载：TypeError: Cannot read property 'compilation' of undefined vue 打包运行npm run build 报错

转载自：https://www.jianshu.com/p/3f8f60e01797

运行npm run build打包时，报错如下：

 

我的package.json如下:

 {
   ...
   "devDependencies": {
     "autoprefixer": "^7.1.2",
     "babel-core": "^6.22.1",
     "babel-eslint": "^8.2.1",
     "babel-helper-vue-jsx-merge-props": "^2.0.3",
     "babel-loader": "^7.1.1",
     "babel-plugin-syntax-jsx": "^6.18.0",
     "babel-plugin-transform-runtime": "^6.22.0",
     "babel-plugin-transform-vue-jsx": "^3.5.0",
     "babel-preset-env": "^1.3.2",
     "babel-preset-stage-2": "^6.22.0",
     "babel-register": "^6.22.0",
     "chalk": "^2.0.1",
     "chromedriver": "^2.27.2",
     "copy-webpack-plugin": "^4.0.1",
     "cross-spawn": "^5.0.1",
     "css-loader": "^2.1.1",
     "element-theme-chalk": "^2.8.2",
     "element-ui": "^2.8.2",
     "eslint": "^4.15.0",
     "eslint-config-standard": "^10.2.1",
     "eslint-friendly-formatter": "^3.0.0",
     "eslint-loader": "^1.7.1",
     "eslint-plugin-import": "^2.7.0",
     "eslint-plugin-node": "^5.2.0",
     "eslint-plugin-promise": "^3.4.0",
     "eslint-plugin-standard": "^3.0.1",
     "eslint-plugin-vue": "^4.0.0",
     "extract-text-webpack-plugin": "^3.0.0",
     "file-loader": "^1.1.11",
     "friendly-errors-webpack-plugin": "^1.6.1",
     "html-webpack-plugin": "^2.30.1",
     "nightwatch": "^1.1.11",
     "node-notifier": "^5.1.2",
     "node-sass": "^4.12.0",
     "optimize-css-assets-webpack-plugin": "^5.0.1",
     "ora": "^1.2.0",
     "portfinder": "^1.0.13",
     "postcss-import": "^11.0.0",
     "postcss-loader": "^2.0.8",
     "postcss-url": "^7.2.1",
     "rimraf": "^2.6.0",
     "rxjs": "^6.5.2",
     "rxjs-compat": "^6.5.2",
     "sass-loader": "^7.1.0",
     "selenium-server": "^3.0.1",
     "semver": "^5.3.0",
     "shelljs": "^0.7.6",
     "style-loader": "^0.23.1",
     "ts-loader": "^3.5.0",
     "typescript": "^3.4.5",
     "uglifyjs-webpack-plugin": "^1.1.1",
     "url-loader": "^1.1.2",
     "vue-class-component": "^7.1.0",
     "vue-i18n": "^8.11.2",
     "vue-i18n-extract": "^0.4.14",
     "vue-loader": "^13.3.0",
     "vue-property-decorator": "^8.1.1",
     "vue-rx": "^6.2.0",
     "vue-style-loader": "^3.0.1",
     "vue-template-compiler": "^2.5.2",
     "vuex": "^3.1.1",
     "webpack": "^3.6.0",
     "webpack-bundle-analyzer": "^3.3.2",
     "webpack-dev-server": "^2.9.1",
     "webpack-merge": "^4.1.0"
   },
   "engines": {
     "node": ">= 6.0.0",
     "npm": ">= 3.0.0"
   },
   "browserslist": [
     "> 1%",
     "last 2 versions",
     "not ie <= 8"
   ]
 }

后来查资料发现是版本问题,webpack是3.6.0的版本，但是optimize-css-assets-webpack-plugin是5.0.1的版本。后来把optimize-css-assets-webpack-plugin改为3.2.0的就可以了。
执行 npm i optimize-css-assets-webpack-plugin@3.2.0就可以改为3.2.0的版本了。
注：如果执行 npm i optimize-css-assets-webpack-plugin@3.2.0完成后出现如下提示，不要按提示执行，会把optimize-css-assets-webpack-plugin恢复到原来的版本，直接忽略提示就好了。

转载自：https://www.jianshu.com/p/3f8f60e01797