fix: angular wrapped mutationobserver detection #1597
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When Angular wraps MutationObserver and rrweb tracks mutations you get trapped in a fight with Angular's changedetection and performance suffers. We had multiple reports at posthog of performance degrading with recording active - even to the point of freezing the page entirely
We discovered that the checks for whether to load mutation observer from an iFrame were not correctly detecting the "taint" of angular wrapping the mutation observer.
So, we need to check for
__zone*
properties added to the prototype tooThis is confirmed as fixing performance issues in posthog-js v 1.187.1