Angular BetterError error

Hi,

I've just tried your better-enum NPM package (0.1.0-dev.12) in an Angular project (Angular v8.2.14) as it sounds like a good solution to an coding issue I have, but it's stopped my Angular project from running. So I ran a "ng build --prod" and it's displaying the following error:

ERROR in ./node_modules/@northscaler/better-error/dist/main/errors/BetterError.js 8:62
Module parse failed: Unexpected token (8:62)
File was processed with these loaders:
 * ./node_modules/@angular-devkit/build-optimizer/src/build-optimizer/webpack-loader.js
You may need an additional loader to handle the result of these loaders.
| exports.BetterError = void 0;
| const lodash_snakecase_1 = __importDefault(require("lodash.snakecase"));
> const upperSnakeCase = (it) => lodash_snakecase_1.default(it)?.toUpperCase();
| /**
|  * A base error class that has `code` & `cause` properties, forming a chain of `Error`s, as well as convenient message & object formatting.

I've also tried downgrading to 11, 10 and 9 in case one of those worked instead, but they all give the same error.