koa2 服务器出现[nodemon] app crashed - waiting for file changes before starting...

If you are encountering the error message "[nodemon] app crashed - waiting for file changes before starting..." when running your Koa2 server with nodemon, it means that there is an error in your code that is causing the server to crash.

To diagnose the issue, you can do the following:

1. Check the logs: When the server crashes, nodemon should print an error message to the console. Look for this message and see if it provides any clues as to what went wrong.

2. Debug the code: Use a debugger to step through your code and identify the problem. You can set breakpoints in your code using the `debugger` statement, or use a tool like VSCode's debugger to step through the code.

3. Check dependencies: Make sure that all the dependencies required by your server are installed and up-to-date.

4. Check file permissions: If your server is trying to access files, make sure that the appropriate file permissions are set.

5. Check network settings: If your server is trying to connect to external resources, make sure that your network settings are configured correctly.

Once you have identified the issue, you can fix the code and restart the server. If you are still encountering issues, feel free to ask me for further assistance.