CustomEvents in addEventListener

[grzegorzkiselev]

Hey, everybody. I am trying to understand the typing of custom events.

I encountered that I can’t specify “CustomEvent” type in addEventListener without patching TS library. Any ideas what I’m doing wrong?

The next question goes further: what can I get by specifying @fires, @listens tags and declaring events via @event? Does this give me any hints, or just display information in the popup?

[samthor]

I don't know if this is what you want, but I wrote up a way in TS (yes, I know this is "types-in-JS", but does importing .d.ts files count?) to somewhat neatly add new event types to classes:

https://github.com/samthor/typed-event-types

[grzegorzkiselev]

Thanks for the answer! Your result was more complicated than I expected. What's confusing to me is that Typescript is not prepared to accept a CustomEvent as an EventListener's callback parameter. Are there any good reasons why it doesn't?