Compiling jscomp to JavaScript

bsb
#1

Tried to include https://raw.githubusercontent.com/BuckleScript/bucklescript/master/jscomp/bin/js_compiler.ml in a project but couldn’t compile it.
The compiler says:
This expression has type bytes but an expression was expected of type string
The folder Readme says to use js_of_ocaml but I don’t understand why can’t it compile regularly.