Opt in for more TS/JS-friendly enum representation.

[back2dos]

It would be nice if there were a way to make the compiler emit code that puts the constructor name into the object (under e.g. a $type property), because that way we could use enums in APIs we expose to other frontend teams (which use JS/TS). Maybe via a compiler flag, that would also control the property name.

[nadako]

Somewhat related to #7165 (still has to rename _hx_index to $index etc). We actually have a define for using name instead of index, but IIRC that's mostly a debugging feature.

[fullofcaffeine]

Yes, please. I just stumbled upon this limitation when using hxtsdgen to directly expose a coconut.data model to TS (it failed when trying to generate tink.core.Noise). See: elsassph/hxtsdgen#28.

[benmerckx]

How about a reference to the constructor/self? Would allow js side to do:

switch (value.$type) {
  case Option.Some:
    console.log(value.v)
    break
  case Option.None:
    console.log('none')
    break
}

Edit: just realized this wouldn't fly in Typescript because it needs a constant type to switch over

[nadako]

Edit: just realized this wouldn't fly in Typescript because it needs a constant type to switch over

This seems to work.

let $:any;

const haxe_ds_Option = {
	None: ($ = {$type: void 0}, $.$type = $, $),
	Some: ($ = function(v:any) { return {$type: $, v: v} }, $)
}

let x = haxe_ds_Option.Some(15);
switch (x.$type) {
	case haxe_ds_Option.None:
		console.log("None");
		break;
	case haxe_ds_Option.Some:
		console.log("Some", x.v);
		break;
}

It doesn't provide any type-safety on TS side though, and I'm not sure it's even possible to have a proper TS "extern" for that without using literal integers/strings.

[benmerckx]

Exactly, I meant Typescript won't be able to distinguish types this way - a constant (or literal) integer or string type would be needed in addition to typing it as a union. Although you can trick it somewhat:

let $:any;

type haxe_ds_Option<T> =
	| {$type: 0}
	| {$type: 1, v: T}

const haxe_ds_Option: {
	None: 0 & haxe_ds_Option<any>,
	Some: 1 & (<T>(v: T) => haxe_ds_Option<T>)
} = {
	None: ($ = {$type: void 0}, $.$type = $, $),
	Some: ($ = function(v:any) { return {$type: $, v: v} }, $)
}

let x = haxe_ds_Option.Some(15);
switch (x.$type) {
	case haxe_ds_Option.None:
		console.log("None");
		break;
	case haxe_ds_Option.Some:
		console.log("Some", x.v);
		break;
}

Playground Link

I guess it's something to solve for external d.ts generators.