custom event API info

[kevinanderson]

addendum to the CustomEvent documentation,  provided by HI support on 1-6-2020

original SN Docs

https://docs.servicenow.com/bundle/newyork-application-development/page/app-store/dev_portal/API_ref...

https://developer.servicenow.com/app.do#!/api_doc?v=newyork&id=customEventClientAPI

/**
* Version of CustomEvent that doesn't require any dependencies. Supports IE9+.
*
* CustomEvent API exposes:
*
* #observe(name, fn)
* register a handler for event (equivalent to #on, but with
* tracing)
*
* #fire(name, payload)
* fire an event on the current frame (equivalent to #fireEvent,
* but with tracing)
*
* #fireUp(name, payload)
* Fire an event recursively up window.parent to the top frame
* starting in the window that fireUp was called.
* Can be stopped by returning false from a registered callback.
*
* #fireTop(name, payload)
* fire an event to this frame and the top frame
*
* #fireAll(name, payload)
* fire an event to the top frame, and then recursively to all its
* children.
*
* #fireToWindow(targetWindow, name, payload, usePostMessage, targetOrigin)
* fire an event to a specified target window
* Optionally usePostMessage with targetOrigin for crossDomain use cases.
*
* #on(event, fn)
* register a handler for event (equivalent to #observe)
*
* #un(event, fn)
* unregister the given handler function from the given event
*
* #unAll(event)
* unregister all handlers for event
*
* #forward(name, element, fn)
* forward the DOM event name on the given element to handler fn
* as a #on() observation
*
* #isFiring()
* true if an event is currently firing, else false
*
* #fireEvent(name, payload)
* fire an event on the current frame
*
*/