* Observes the given element by using the existing MutationObserver if available, or creating a * new one if not.
(element: Element)
| 123 | * new one if not. |
| 124 | */ |
| 125 | private _observeElement(element: Element): Subject<MutationRecord[]> { |
| 126 | return this._ngZone.runOutsideAngular(() => { |
| 127 | if (!this._observedElements.has(element)) { |
| 128 | const stream = new Subject<MutationRecord[]>(); |
| 129 | const observer = this._mutationObserverFactory.create(mutations => stream.next(mutations)); |
| 130 | if (observer) { |
| 131 | observer.observe(element, { |
| 132 | characterData: true, |
| 133 | childList: true, |
| 134 | subtree: true, |
| 135 | }); |
| 136 | } |
| 137 | this._observedElements.set(element, {observer, stream, count: 1}); |
| 138 | } else { |
| 139 | this._observedElements.get(element)!.count++; |
| 140 | } |
| 141 | return this._observedElements.get(element)!.stream; |
| 142 | }); |
| 143 | } |
| 144 | |
| 145 | /** |
| 146 | * Un-observes the given element and cleans up the underlying MutationObserver if nobody else is |