promises rejected with a specific error are not of the original type when they are caught (v0.8.10 reproduction included)

[dbpieter]

When a promise is rejected with a specific error it is not of the same type once it is caught.
REPRO: https://plnkr.co/edit/7fASDCWYk0kRqax5oUWz?p=preview

class MyError extends Error {}

Promise.reject(new MyError()).catch((err) => {
  if(err instanceof MyError) {
    console.log('workz')
  } else {
    console.log('wtf!') // zone v0.8.10 :(
  }
})

This doesn't work as expected when zone v0.8.10 is loaded.
Loading 'zone-js/dist/zone-error.js' fixes the issue. Is it meant to be lke this.

Seems strange this additional script needs to be loaded in order for Zone to not shadow error types.
Zone should be completely transparant right ?

[JiaLiPassion]

@dbpieter , I don't think this behavior related to zone.js, you can just try use typescript 2.x to write this sample code.

class MyError extends Error {}

const error = new MyError();

console.log('instanceof', error instanceof MyError);

the result will be false.

The typescript compiled code will look like.

var MyError = (function (_super) {
    __extends(MyError, _super);
    function MyError() {
        return _super.apply(this, arguments) || this;
    }
    return MyError;
}(Error));

the new MyError() will always return an Error instance not a MyError.

So this is more like a typescript behavior.

When you load zone-js/dist/zone-error.js, new MyError() will return MyError instance.

[dbpieter]

@JiaLiPassion. Thx for your explanation. The behaviour changed with zone v0.8.10 so I thought this was zone related.

It seems it is better not to extend from Error at all.