Unable to index file
A comment of the OP on this answer reveals the cause:
I now removed the
aux.jsand now everything works fine.
AUX is a special file name in Windows (inherited from the old ages of MS-DOS). It is a special file that denotes a device. While on other OSes (Unix-based) the special device files are located in the /dev directory, MS-DOS (and its successor Windows) recognizes the name in any directory and treats it as a special file. This certainly happens in the Command Prompt (for compatibility with the old MS-DOS programs) but it seems it happens in other contexts too.
The name being special and recognized in any directory, the OS code that handles the file names ignores the provided aux.js file (and its path) and handles aux as the special device file AUX. The character case is not important, on Windows file systems aux and Aux are the same as AUX. Because it thinks it has found a special name, it ignores the file extension.
The same thing happens for NUL, CON, PRN and other special names. Check the complete list here: https://en.wikipedia.org/wiki/Device_file#MS-DOS
There is no solution for this, only workarounds. If you are stuck on Windows or the project is developed on Windows by coworkers, the only way to circumvent this is to avoid these special names. Aux is probably the short of Auxiliary.
Use longer names.
An interesting reading (and the source of wisdom that provided the information I put into this answer) is this article written by Microsoft senior developer Raymond Chen on his blog "The Old New Thing" in 2003.
Even I was facing the same issue that because Aux is a special name in windows. You can rename Aux file "Auxiliary" which will work un doubtedly.