Rework IntersectionObserver #1130
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karlseguin
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Previously, we were reusing the same page for all cases. But that causes an issue with lightpanda-io/browser#1130 and, from Google AI answer, seems to be a common cause of various errors (network, timeouts, ...) For us, the specific problem is that puppeteer registers an IntersectionObserver (why?), but the scrip then does another page.goto, preventing the IntersectionObserver from ever calling back. This ends up blocking puppeteer. It wasn't an issue before, because we fired the callback synchronously. But that was not a correct behavior. This is probably something we should support, but it isn't clear how. Does Chrome keep the "old" page context around to fulfill these events?
1 - Always fire the callback on the next tick. This is probably the most important change, as frameworks like React don't react well if the callback is fired immediately (they expect to continue processing the page in its current state, not in the mutated state from the callback) 2 - Always fire the callback for observed elements with a parent, whether or not those intersect or are connected. From MDN, the callback is fired "The first time the observer is initially asked to watch a target element." 3 - Add a mutation observer so that if a node is added to the root (or removed) the callback is fired. This, I think, is the best we can currently do for "intersection".
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1 - Always fire the callback on the next tick. This is probably the most important change, as frameworks like React don't react well if the callback is fired immediately (they expect to continue processing the page in its current state, not in the mutated state from the callback)
2 - Always fire the callback for observed elements with a parent, whether or not those intersect or are connected. From MDN, the callback is fired "The first time the observer is initially asked to watch a target element."
3 - Add a mutation observer so that if a node is added to the root (or removed) the callback is fired. This, I think, is the best we can currently do for "intersection".