Certain types such as MouseEvent.button not defined

I noticed some values for types such as MouseEvent.button are defined in Web API specs but are not defined in lib.dom.ts:

0: Main button pressed, usually the left button or the un-initialized state
1: Auxiliary button pressed, usually the wheel button or the middle button (if present)
2: Secondary button pressed, usually the right button
3: Fourth button, typically the Browser Back button
4: Fifth button, typically the Browser Forward button

If this is intentional, I’m wondering what the rationale is. (I could not find any similar issues or couldn’t find the right terms.)

terms: MouseEvent, button

[HolgerJeromin]

They are not defined in the browsers (others like WebSocket.CLOSED are). So defining them would be an TypeScript only invention. I don’t think this would align to the mission of TypeScript.

[github-actions[bot]]

Closing because @saschanaz is one of the code-owners of this repository.