Module not found: Error: Can‘t resolve ‘core-js/modules/es.promise.js‘

1.遇到的问题 

 具体错误： 

ERROR in ./src/js/index.js 1:0-48
产环境配置15js兼容性处理srcjs'ERROR in ./src/js/index.js 2:0-39
Module not found: Error: Can't resolve 'core-js/modules/es.promise.js' in 'D:DesktopMy FilesRecentlyStudyWebPackdemo3.webpack生产环境配 
置15js兼容性处理srcjs'ERROR in ./src/js/index.js 3:0-39
Module not found: Error: Can't resolve 'core-js/modules/web.timers.js' in 'D:DesktopMy FilesRecentlyStudyWebPackdemo3.webpack生产环境配 3 errors have detailed information that is not shown.
Use 'stats.errorDetails: true' resp. '--stats-error-details' to show it.

2.解决办法

原因是未安装core-js
在package.json所在目录  

npm i core-js -D