Discussion: access to globals from components

[dvoytenko]

Some globals are ok, such as IntersectionObserver, etc. But many could be harmful for components running inside friendly iframes. For instance window.location.href could be different from component.baseElement.ownerDocument.defaultView.location.href. Some specific points:

• A component running inside a friendly iframe could have a completely different baseURI and thus could be resolving URLs incorrectly.
• Use of global setTimeout, setInterval, and event listeners (e.g. window.onresize) could cause memory leaks when a friendly iframe is removed.
• Rare, but if a component needs to call document.querySelector() and would do it on a wrong document, it won't find what's it looking for.