ERROR Failed to compile with 541 errors 11:27:44 These dependencies were not found: * core-js/modules/es.array.concat.js in ./node_modules/cache-loader/dist/cjs.js??ref--12-0!./

 ERROR  Failed to compile with 541 errors                                                                                                       11:27:44

These dependencies were not found:

* core-js/modules/es.array.concat.js in ./node_modules/cache-loader/dist/cjs.js??ref--12-0!./

项目打包时出现了这种问题，是一个叫core-js的包出了问题；

解决方法是
1.是版本的问题，要重新install一下

npm install core-js@3 --save

# or

npm install core-js@2 --save

2.也有人给出了这种方法：（我用这种方法还是出现了些问题，如果上面那种方式没有解决你的问题，你可以再试试这种方式；或者两种方式都用，未尝不可。）

//在babel.config.js中添加

presets: [ [ "@vue/app", { useBuiltIns: "entry" } ] ]

详情参考这里：

useBuiltIns
core-js module error

接下来：
你可能出现过这种问题，没有直接忽视；

 ERROR  Failed to compile with 17 errors                                                                                                                   16:27:36
 error  in ./node_modules/vant/es/nav-bar/index.css

Module build failed (from ./node_modules/postcss-loader/src/index.js):
Error: Loading PostCSS Plugin failed: Cannot find module 'postcss-pxtorem'

(@C:\Users\1234Wu\Desktop\eMeetUser\emeet_usermanual\.postcssrc.js)
    at load (C:\Users\1234Wu\Desktop\eMeetUser\emeet_usermanual\node_modules\postcss-load-config\src\plugins.js:28:11)
    at Object.keys.filter.map (C:\Users\1234Wu\Desktop\eMeetUser\emeet_usermanual\node_modules\postcss-load-config\src\plugins.js:53:16)
    at Array.map (<anonymous>)
    at plugins (C:\Users\1234Wu\Desktop\eMeetUser\emeet_usermanual\node_modules\postcss-load-config\src\plugins.js:52:8)
    at processResult (C:\Users\1234Wu\Desktop\eMeetUser\emeet_usermanual\node_modules\postcss-load-config\src\index.js:33:14)
    at config.search.then (C:\Users\1234Wu\Desktop\eMeetUser\emeet_usermanual\node_modules\postcss-load-config\src\index.js:94:14)

 @ ./node_modules/vant/es/nav-bar/index.css 4:14-143 14:3-18:5 15:22-151
 @ ./node_modules/vant/es/nav-bar/style/index.js
 @ ./src/main.ts
 @ multi (webpack)-dev-server/client?http://192.168.1.5:80/sockjs-node (webpack)/hot/dev-server.js ./src/main.ts

 error  in ./src/App.vue?vue&type=style&index=0&lang=less&

Module build failed (from ./node_modules/postcss-loader/src/index.js):
Error: Loading PostCSS Plugin failed: Cannot find module 'postcss-pxtorem