How to debug Parcel itself?

[episage]

Hi, I tried to

PARCEL_WORKERS=1 PARCEL_MAX_CONCURRENT_CALLS=1 node --inspect-brk ./node_modules/.bin/parcel --log-level 3 --no-cache src/index.html

but Chrome Debugger never catches my explicit debugger; inside a transformer. Parcel just happily displays that the build has been finished and is watching for changes...

"use strict";

Object.defineProperty(exports, "__esModule", {
    value: true
});
exports.default = void 0;

var _plugin = require("@parcel/plugin");

var _default = new _plugin.Transformer({
    transform({
        asset
    }) {
        console.error(`WADAFAK!!!!`);  
        debugger;
        process.stdout.write('HUUUUUUUUUUU') 
        asset.isIsolated = true;
        return [asset];
    }

});

exports.default = _default;

(src/index has similar code with debugger; as well)

package.json for transformer:

{
    "name": "parcel-transformer-xhtml",
    "version": "1.0.0",
    "description": "",
    "main": "lib/index.js",
    "publishConfig": {
      "access": "public"
    },
    "source": "src/index.js",
    "engines": {
      "node": ">= 8.0.0",
      "parcel": "^2.0.0-alpha.1.1"
    },
    "dependencies": {
      "@parcel/plugin": "^2.0.0-alpha.1.1"
    }
  }

Config is declared as

{
    "extends": "@parcel/config-default",
    "transformers": {
        "*.xhtml": ["parcel-transformer-xhtml"]
    }
}

Any hints?

[episage]

Use PARCEL_WORKERS=0 and it stops!

[mischnic]

In the past, I've had success with https://github.com/GoogleChromeLabs/ndb. I think node doesn't support debugging worker threads (which is why PARCEL_WORKERS=0 works - then everything is in the main thread)