Allow extending of event objects

• Component: DOM
• Status: RESOLVED CONFIGURATION CHANGED

[Jake Archibald]

class Foo extends Event {}
console.log(new Foo('bar').constructor);

Chrome & Firefox say Foo, Edge & Safari say Event.

The Chrome/Firefox behaviour is preferable, as it allows you to create custom event objects, which is especially useful when developing custom elements.

[Jake Archibald]

Tests: http://w3c-test.org/dom/events/Event-subclasses-constructors.html

[Lucas Forschler]

Mass move bugs into the DOM component.

[Alexey Shvayka]

(In reply to Jake Archibald from comment #1)
> Tests: http://w3c-test.org/dom/events/Event-subclasses-constructors.html

As of r256716, extending Event (as well as other DOM constructors) works as expected.
Provided test file is 100% passing.