example.dart

class HelloException implements Exception {
  String cause;

  HelloException(this.cause);
}

main() {
  var a = 1;

  try {
    if (a != 2) {
      throw new HelloException('OMG');
    }
  } on HelloException {
    print('hello exception');
  } on Exception catch (e) {
    print('no, no');
  }
}

example.js

export const lib__example = Object.create(null);
import { core, dart, dartx } from 'dart_sdk';
let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
lib__example.HelloException = class HelloException extends core.Object {
  new(cause) {
    this.cause = cause;
  }
};
lib__example.HelloException[dart.implements] = () => [core.Exception];
dart.setSignature(lib__example.HelloException, {
  constructors: () => ({new: dart.definiteFunctionType(lib__example.HelloException, [core.String])}),
  fields: () => ({cause: core.String})
});
lib__example.main = function() {
  let a = 1;
  try {
    if (a != 2) {
      dart.throw(new lib__example.HelloException('OMG'));
    }
  } catch (e$) {
    if (lib__example.HelloException.is(e$)) {
      core.print('hello exception');
    } else if (core.Exception.is(e$)) {
      let e = e$;
      core.print('no, no');
    } else
      throw e$;
  }

};
dart.fn(lib__example.main, VoidTodynamic());

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