How to remove whitespace from field tags if used as PDF File Name Prefix?

Hey there, I want to use a field tag as prefix for the PDF file name. It’s working great, unless there isn’t some whitspace in the field.

If there is whitespace the filename will have on too, and so I’m getting 404 if I try to open the file by clicking the link in the medialibrary.

Is there any way to sanitize the value from the field tag before creating the filename?

Thank you!