requiremainfilename Uncaught TypeError Cannot read property filename of undefined

This error occurs when you try to access the filename property of the main module using require.main.filename but the main module is not defined.

The main module is the module that was initially run by Node.js and is the entry point of the application. When a module is run as the main module, require.main will be set to that module.

To fix this error, make sure that you are running your code as the main module or that you are requiring a module that has a main property. You can also check if require.main is defined before accessing its properties to avoid this error