Type inference doesn't work for switch-case of 'constructor' property

[Sgt-Nukem]

Search Terms

constructor type inference switch case

Suggestion

Let a switch (XXX.constructor) correctly infer types in case blocks.

Example

c.f. the following snippet (the Router is the Angular Router btw)

In case NavigationError: block it should be clear that event is indeed a NavigationError instance and I would like to get IntelliSense for that.

As NavigationError has an error property (c.f. following image) I would expect to get that shown in the IntelliSense tooltip in the image above -- but I get console.error() only!

[nmain]

There's nothing special about switch here; the pattern foo.constructor just isn't recognized for narrowing at all: https://www.typescriptlang.org/play/#src=declare%20var%20e%3A%20Event%3B%0D%0A%0D%0Aif%20(e%20instanceof%20MouseEvent)%20%7B%0D%0A%20%20e.pageX%3B%20%2F%2F%20works%0D%0A%7D%0D%0A%0D%0Aif%20(e.constructor%20%3D%3D%3D%20MouseEvent)%20%7B%0D%0A%20%20e.pageX%3B%20%2F%2F%20doesn't%20work%0D%0A%7D%0D%0A

Duplicate of #23274

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.

[murbanowicz]

As #23274 does not fix the case for switch I think this one should be re-opened.