I'm trying nodejs/jsfs and get a node runtime error "TypeError: c_1455079.charCodeAt is not a function".

Here my little program read_try.nim:

import nodejs/jsfs

requireFs()
let data = readFileSync("sometext.txt")
echo $data

and I compile it with

nim js read_try.nim

Does this maybe means, node cannot find the file sometext.txt? But sounds weird to me.