Correctly handle different javascript realms/documents #147
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This does not support elements coming from a third realm, different from the one we are running and the one the document belongs to, but this is even less common than having to deal with crossrealm elements to begin with. (And impossible on Firefox)
edave64
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In JavaScript, multiple different global contexts (realms) can exist with their own classes and document (https://tc39.es/ecma262/#realm) and they can access each others objects.
These realms are created by calls to
window.openor when using<iframe>s. An application I am working on enables multi-monitor support by opening multiple browser windows that are all controlled from the primary tab. And Quill does not function correctly when initialized in one of these external windows.This can lead to very unintuitive behavior, since using the global
documentcan lead to incorrect results andinstanceofunexpectedly returningfalse. And because of https://bugzilla.mozilla.org/show_bug.cgi?id=1470017 in FireFox, we cannot even control what realm our initial objects are part of.Luckily,
nodesown references to theirownerDocument, which has a reference to theirdefaultView, making it possible to write code that survives these conditions.This PR removes the expectation that
documentis the only document that can exist and fixes aninstanceof Element, that were hindering Quill from working correctly when initializing it in an iframe.The Quill PR is prepared, but parchment needs to be updated for the E2E tests to pass in Firefox.