Babylon.js: BabylonJS Typescript imports fail for MochaJS specs

While attempting to set up a unit testing environment that involves MochaJS and BabylonJS, the importing of BabylonJS parts threw two types of errors:

1. SyntaxError: Named export 'Camera' not found.
2. SyntaxError: Cannot use import statement outside a module. Tests are running with a dedicated tsconfig.json and a .mocharc.js config. This GitHub repo contains a full test and demo setup.

Comparison was made to Typestrong/ts-node-repros example repo.

Key facts:

1. Node Version: 14.17.0
2. Mocha: loader: 'ts-node/esm'
3. package.json: "type": "module"
4. TS config:

{
	"compilerOptions": {
		"module": "ES2020",
		"target": "ES2020",
		"moduleResolution": "node",
		"esModuleInterop": true
	}
}

Note: All Mocha options can be found here.

Repro

• Bug repro on playground: As the tests are running in the CLI and as it’s about imports, the issue can not get reproduced in the playground. Please refer to this this GitHub repo for a reproduction: Clone and run either of npm run test-{A|B}.
• Expected result:
• Current result: See Console error log below.

Screenshots Console error log

Test case A

$ npm run test-A

> demo/ts-mocha-babylonjs@0.1.0 test-A
> ./node_modules/.bin/mocha --config .mocharc-A.cjs -P ./tsconfig.json

(node:133305) ExperimentalWarning: --experimental-loader is an experimental feature. This feature could change at any time

/path/to/ts-mocha-babylonjs/tests/case-A.spec.ts:13
import { Camera } from '@babylonjs/core/Cameras/camera.js';
         ^^^^^^
SyntaxError: Named export 'Camera' not found. The requested module '@babylonjs/core/Cameras/camera.js' is a CommonJS module, which may not support all module.exports as named exports.
CommonJS modules can always be imported via the default export, for example using:

import pkg from '@babylonjs/core/Cameras/camera.js';
const { Camera } = pkg;

    at ModuleJob._instantiate (internal/modules/esm/module_job.js:97:21)
    at ModuleJob.run (internal/modules/esm/module_job.js:142:20)
    at Loader.import (internal/modules/esm/loader.js:182:24)
    at formattedImport (/path/to/projects/ts-mocha-babylonjs/node_modules/mocha/lib/esm-utils.js:7:14)
    at Object.exports.loadFilesAsync (/path/to/projects/ts-mocha-babylonjs/node_modules/mocha/lib/esm-utils.js:55:20)
    at singleRun (/path/to/projects/ts-mocha-babylonjs/node_modules/mocha/lib/cli/run-helpers.js:125:3)
    at Object.exports.handler (/path/to/projects/ts-mocha-babylonjs/node_modules/mocha/lib/cli/run.js:362:5)

Test case B

$ npm run test-B

> demo/ts-mocha-babylonjs@0.1.0 test-B
> ./node_modules/.bin/mocha --config .mocharc-B.cjs -P ./tsconfig.json

(node:133357) ExperimentalWarning: --experimental-loader is an experimental feature. This feature could change at any time
(node:133357) Warning: To load an ES module, set "type": "module" in the package.json or use the .mjs extension.

/path/to/projects/ts-mocha-babylonjs/node_modules/@babylonjs/core/Cameras/camera.js:1
import { __decorate, __extends } from "tslib";
^^^^^^

SyntaxError: Cannot use import statement outside a module
    at wrapSafe (internal/modules/cjs/loader.js:915:16)
    at Module._compile (internal/modules/cjs/loader.js:963:27)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1027:10)
    at Module.load (internal/modules/cjs/loader.js:863:32)
    at Function.Module._load (internal/modules/cjs/loader.js:708:14)
    at ModuleWrap.<anonymous> (internal/modules/esm/translators.js:195:29)
    at ModuleJob.run (internal/modules/esm/module_job.js:145:37)
    at Loader.import (internal/modules/esm/loader.js:182:24)
    at formattedImport (/path/to/projects/ts-mocha-babylonjs/node_modules/mocha/lib/esm-utils.js:7:14)
    at Object.exports.loadFilesAsync (/path/to/projects/ts-mocha-babylonjs/node_modules/mocha/lib/esm-utils.js:55:20)
    at singleRun (/path/to/projects/ts-mocha-babylonjs/node_modules/mocha/lib/cli/run-helpers.js:125:3)
    at Object.exports.handler (/path/to/projects/ts-mocha-babylonjs/node_modules/mocha/lib/cli/run.js:362:5)