Migrate to ESM only

[43081j]

Fixes #1429

cc @paulmillr

i ran it through arethetypeswrong and all seems to be good

[paulmillr]

Three things:

1. why keep exports? They aren’t nevessary anymore
2. Don’t we need “types” root property?
3. Could you launch node index.ts? That would ensure nodejs can read typescript (erasable syntax)

[43081j]

1. It can be useful for controlling which files are exposed. We can simplify it to a flat object though. Without it, it'd probably work fine but mean people can import other files we ship too. No strong opinion though - I'd keep it but flatten it but happy to also remove it
2. We don't anymore since the dts are alongside the js files, so typescript will pick them up automatically
3. If it isn't already, it would be good to turn on erasable syntax only too

[paulmillr]

1. “Files” control which files are in package, not “exports”. I think it doesn’t matter if *handler files are exposed.
2. In the past there were some issues with ts not picking it up even while being in same root dir. maybe it’s fixed now
3. jsbt has erasable syntax tsconfig setting, which we inherit — but useful to test it manually just in case

[43081j]

1. Files controls what we ship, exports controls what you can import. But again I don't mind either way since we're exporting every js file pretty much
2. It should be fine now 👍
3. I can add a test when I get chance

[43081j]

we can't actually do the typescript test since chokidar itself can't be loaded that way

all of our imports correctly reference .js files right now, since that's what will exist at run-time

if we wanted to run chokidar itself from typescript sources, we'd need to configure typescript to use .ts extension in imports (i.e. transform import paths from .ts to .js at build time. since the run-time js still needs .js imports but the sources need .ts imports)

though im not sure any of this matters to us. anyone can import chokidar fine right now in their own typescript executed directly through node. the only people who would want to run chokidar itself on the command line are probably us

we could have a test that runs some typescript that imports chokidar, but what have we achieved by doing that? it just means importing chokidar works and we already know that

[paulmillr]

transform import paths from .ts to .js at build time

that’s what I do in all noble repos. Jsbt is already prepared for it. It’s just an option in typescript

[43081j]

Where would we be executing chokidar itself through node?

Won't it always be imported?

I know we can flip the flag in tsconfig. Just want to understand where we'd use it though

Either way we probably should tackle it in a separate issue/pr