As @domenic mentioned in https://github.com/whatwg/dom/issues/414 some UI events, such as MouseEvent and KeyboardEvent, do not have a straight mapping from initializing dictionary member to internal state. For those event classes the DOM Standard has "event constructing steps", added in https://github.com/whatwg/dom/pull/614.
annevk
commented
6 years ago
As @domenic mentioned in https://github.com/whatwg/dom/issues/414 some UI events, such as
MouseEventandKeyboardEvent, do not have a straight mapping from initializing dictionary member to internal state. For those event classes the DOM Standard has "event constructing steps", added in https://github.com/whatwg/dom/pull/614.