JS file format of (js_of_ocaml (javascript_files ...))

Learning
1

dune file:

(library
 (name code_mirror)
 (js_of_ocaml (javascript_files ./babel_out.js))
 (libraries brr js_of_ocaml))

Now, what format is “babel_out.js” expected to be in ?

Consider the following Makefile:

default:
	# esbuild includes.js --target=es6 --format=esm --bundle --outfile=out.js
	esbuild includes.js --bundle --outfile=es_out.js
	./node_modules/@babel/cli/bin/babel.js es_out.js --config-file ./babel.config.js -o babel_out.js

jsoo is NOT happy with the file es_out.js (parsing error), but okay with the file babel_out.js

My babel.config.js is:

 cat babel.config.js 
module.exports = {
  presets: ["@babel/env"],
  plugins: ["@babel/transform-property-mutators"],
  compact: true
};

===

I’m trying to drop the babel.js step and only use esbuild, as esbuild is very fast and babel.js is very slow.

2

The next version of jsoo will come with improved support for es6 (see Compiler: modernize js parser by hhugo · Pull Request #1391 · ocsigen/js_of_ocaml · GitHub). In short, export and import syntax are still missing.

3

Okay, I guess this is the point of plugins: ["@babel/transform-property-mutators"], from babel.config.js ? Do you know if there is a way to do this from esbuild ? Googling brings up babel, but not esbuild solutions. Thanks!