webpack报错，运行npm run build报The ‘mode‘ option has not been set, webpack will fallback to ‘production‘

 打包分开发环境和生产环境

需要在文件 package.json 修改、添加红圈中的内容

 

"dev": "webpack --mode development",  
"build": "webpack --mode production"

详解可见官方文档：https://webpack.js.org/configuration/mode/#usage