Typescript Union type allows attributes from both interfaces

Asked Jul 30 '19 at 00:56

Active Jul 30 '19 at 01:21

Viewed 25 times

interface NumericalityGreaterOptions {
  greaterThan?: number;
  greaterThanOrEqualTo?: number;
}

interface NumericalityEqualOptions {
  equalTo?: number;
}

const x: NumericalityEqualOptions | NumericalityGreaterOptions = {
  greaterThanOrEqualTo: 4,
  equalTo: 3
};

https://www.typescriptlang.org/play/#code/JYOwLgpgTgZghgYwgAgHIFcC21gLgG2DAE8BxKCOSKAeQAcxgB7EAZ2QG8BYAKGWQDmFKtAAqACzggA-AC5kILACNoAbl78hlahKk0oAUQCO6AqKZyFytbwC+vXqGrwkaLDjyESx0-nqMWdm4+ZAgTMwt5RUwVKHUeex5eBECwZAAPeQxsKFwCImIfAn9mNmQAHzccvK8yYWoSwOQAXk4NQXqxSRB9IvxzeQAWABp2sN8B5ABmO1UgA I would however expect typescript to not allow x to have equalTo and greaterThanOrEqualTo as attributes as they are from different interfaces which are combined via a union type. I would expect this behaviour from:

NumericalityEqualOptions & NumericalityGreaterOptions

instead.

Am I doing something wrong or is this a bug?

edited Jul 30 '19 at 01:21

asked Jul 30 '19 at 00:56

Maurice Döpke

1

The link you provided DOES NOT pass type check. – zerkms Jul 30 '19 at 00:58
@zerkms I accidentally typed "greaterThanOrEqualTo" as a date instead of a number. Now it throws no error even though it should. – Maurice Döpke Jul 30 '19 at 01:22
1

@MauriceDöpke I think the duplicate answers this nicely, let me know if you think it does not solve the problem. – Titian Cernicova-Dragomir Jul 30 '19 at 01:27

Typescript Union type allows attributes from both interfaces

0 Answers0