as a result of ：
After importing the project project.config.json The file was modified by wechat developer tools .
solve ：
Missing code ：“miniprogramRoot”: “./unpackage/dist/dev/mp-weixin”.“miniprogramRoot” Is the directory of the specified applet source code ( Need to be relative path ).
Just lock to /dist/dev/mp-weixin The catalogue will do , Everyone's directory structure may be different , You can look in various directories , Look where there is dist Catalog , Then you can find it .
thank