internal/modules/cjs/loader.js:883
throw err;
^

Error: Cannot find module ‘D:\app.js’
[90m at Function.Module._resolveFilename (internal/modules/cjs/loader.js:880:15)[39m
[90m at Function.Module._load (internal/modules/cjs/loader.js:725:27)[39m
[90m at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12)[39m
[90m at internal/main/run_main_module.js:17:47[39m {
code: [32m’MODULE_NOT_FOUND’[39m,
requireStack: []
}
解决方法： 先将node_modules文件夹删除；
再在Windows PowerShell中执行npm install后在重新输入node app.js启动就好了

若后面报：
D:\Vue项目\vue\api-serve\node_modules\mysql\lib\protocol\Parser.js:437
throw err; // Rethrow non-MySQL errors
^

Error: ER_ACCESS_DENIED_ERROR: Access denied for user ‘root’@‘localhost’ (using password: YES)
at Handshake.Sequence._packetToError (D:\Vue项目\vue\api-serve\node_modules\mysql\lib\protocol\sequences\Sequence.js:47:14)
at Handshake.ErrorPacket (D:\Vue项目\vue\api-serve\node_modules\mysql\lib\protocol\sequences\Handshake.js:123:18)
at Protocol._parsePacket (D:\Vue项目\vue\api-serve\node_modules\mysql\lib\protocol\Protocol.js:291:23)

解决方法：在该文件中找到config文件夹打开default.json将里面的“user”改为数据库的用户名，“password”改为自己数据库的密码