Auxclick event handler has arg with Event interface

[Thisman]

TypeScript Version: 3.3.3
Code

const handler = (event: MouseEvent) => {}
document.addEventListener('click', handler); // OK
document.addEventListener('auxclick', handler); // NOT OK:(

Actual behavior: throw error

Argument of type '(event: MouseEvent) => void' is not assignable to parameter of type 'EventListenerOrEventListenerObject'.
  Type '(event: MouseEvent) => void' is not assignable to type 'EventListener'.
    Types of parameters 'event' and 'evt' are incompatible.
      Type 'Event' is missing the following properties from type 'MouseEvent': altKey, button, buttons, clientX, and 25 more.

Playground Link: http://www.typescriptlang.org/play/index.html#src=const%20handler%20%3D%20(e%3A%20MouseEvent)%20%3D>%20%7B%20%7D%3B%0D%0A%0D%0Adocument.addEventListener('click'%2C%20handler)%3B%0D%0Adocument.addEventListener('auxclick'%2C%20handler)%3B
(need to strictFunctionTypes on )

Is this bug or expected behavior? MDN says what auxlick has MouseEvent interface https://developer.mozilla.org/en-US/docs/Web/Events/auxclick

[dragomirtitian]

@Thisman Your playground link is broken(it's just a playground link does not contain the actual code, it should be encoded in the URL)

[Thisman]

@Thisman Your playground link is broken(it's just a playground link does not contain the actual code, it should be encoded in the URL)

@dragomirtitian update link. For see error need to on strictFunctionTypes option on ( link didn't save that param )

[sandersn]

https://html.spec.whatwg.org/multipage/webappapis.html#idl-definitions gives the type as EventHandler, which is why it uses that type in lib.dom.d.ts.

I noticed that the MDN link you gave doesn't have a link to the spec. Confusingly, the spec links to a different MDN page for GlobalEventHandlers, which in turns links to a different spec, for UI Events.

The first spec, which we use right now, specifies event: Event. The second spec specifies event: MouseEvent. Perhaps the problem is that we need to switch that spec for this type.

@saschanaz Do you know whether HTML - Web application APIs is the right spec for auxclick, or UI Events?

[saschanaz]

EventHandler itself does not say anything about which event object should be used. We should add that information in addedTypes.json. The HTML spec links to UI Event and per the spec it should use MouseEvent.