How do I get the name of a selected file in android?

I am building a mobile app with meteor. Somewhere in my template I have the following code for reading the filenames, filesize and extension. The event is coming from an <input type="file"/> element.

const media_file =[0]
const filename =
const fsize = media_file.size
const filetype = media_file.type
const extension = filename.slice(filename.lastIndexOf('.') + 1)

This works fine on a browser. But on mobile (android) build, the filename and extension reports a number. Any idea how I might read the filename and extention? The filesize turns out fine.