Provide a way for zonejs to not patch MutationObserver

[mjyocca]

🐞 bug report

Affected Package

The issue is caused by package @angular/zone.js

Description

Our application runs Angular and Salesforce's Lightning Web Components in the same document. A component in their library depends on the MutationObserver to be the native implementation. Zone.js patches the MutationObserver unless we set flag, __Zone_disable_EventTarget = true. However we do not wish to set that flag.

Only work around that we found is to re-assign the Native Code implementation for MutationObserver found by window[Zone.__symbol__("MutationObserver")] before we load the component.

Wish for guidance or a solution to set zone.js to not patch the MutationObserver.

[mjyocca]

@niralpokal

[splincode]

@JiaLiPassion Hmm, when I pass __Zone_disable_EventTarget = true for experiment

I have failed in my app

oriAddListener - is undefined

[JiaLiPassion]

@mjyocca , there is a PR for this purpose #31657, since it is a breaking change, I will work on it for the next major version, your current walk around (re-assign the native MutationObserver is totally fine).

@splincode , could you give me a reproduce repo?

[mjyocca]

@JiaLiPassion, If we go w/ re-assigning the MutationObserver manually, are there any angular features we should not use or be aware of?

[JiaLiPassion]

@mjyocca, if you reassign the MutationObserver, the callbacks of MutationObserver will not in the ngZone, so if some data changed in the callbacks, it will not trigger change detection and reflected in the view, beside that, there are no other impacts.

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