fix(40454): allow IntersectionObserverInit.root to accept type Docume… (#909)

* fix(40454): update IDL url for Intersection Observer and add type map from undefined to void

* Remove change in helpers.ts

Author: troyt-42

baselines/dom.generated.d.ts

@@ -611,7 +611,7 @@ interface IntersectionObserverEntryInit {
 }
 
 interface IntersectionObserverInit {
-    root?: Element | null;
+    root?: Element | Document | null;
     rootMargin?: string;
     threshold?: number | number[];
 }
@@ -9623,7 +9623,7 @@ declare var InputEvent: {
 
 /** provides a way to asynchronously observe changes in the intersection of a target element with an ancestor element or with a top-level document's viewport. */
 interface IntersectionObserver {
-    readonly root: Element | null;
+    readonly root: Element | Document | null;
     readonly rootMargin: string;
     readonly thresholds: ReadonlyArray<number>;
     disconnect(): void;

inputfiles/idl/Intersection Observer.widl

@@ -1,19 +1,20 @@
-callback IntersectionObserverCallback = void (sequence<IntersectionObserverEntry> entries, IntersectionObserver observer);
+callback IntersectionObserverCallback = undefined (sequence<IntersectionObserverEntry> entries, IntersectionObserver observer);
 
-[Constructor(IntersectionObserverCallback callback, optional IntersectionObserverInit options),
- Exposed=Window]
+[Exposed=Window]
 interface IntersectionObserver {
-  readonly attribute Element? root;
+  constructor(IntersectionObserverCallback callback, optional IntersectionObserverInit options = {});
+  readonly attribute (Element or Document)? root;
   readonly attribute DOMString rootMargin;
   readonly attribute FrozenArray<double> thresholds;
-  void observe(Element target);
-  void unobserve(Element target);
-  void disconnect();
+  undefined observe(Element target);
+  undefined unobserve(Element target);
+  undefined disconnect();
   sequence<IntersectionObserverEntry> takeRecords();
 };
 
-[Constructor(IntersectionObserverEntryInit intersectionObserverEntryInit)]
+[Exposed=Window]
 interface IntersectionObserverEntry {
+  constructor(IntersectionObserverEntryInit intersectionObserverEntryInit);
   readonly attribute DOMHighResTimeStamp time;
   readonly attribute DOMRectReadOnly? rootBounds;
   readonly attribute DOMRectReadOnly boundingClientRect;
@@ -34,7 +35,7 @@ dictionary IntersectionObserverEntryInit {
 };
 
 dictionary IntersectionObserverInit {
-  Element?  root = null;
+  (Element or Document)?  root = null;
   DOMString rootMargin = "0px";
   (double or sequence<double>) threshold = 0;
 };

inputfiles/idlSources.json

@@ -387,7 +387,7 @@
         "title": "Indexed Database"
     },
     {
-        "url": "https://www.w3.org/TR/intersection-observer/",
+        "url": "https://w3c.github.io/IntersectionObserver/",
         "title": "Intersection Observer"
     },
     {