Phew. What a difference a `:last` makes in jQuery. Third-party @shopify app with a very long list of selectors in a click handler. With the deprecated `:last` selector: ~616ms Without: ~16ms (Talked to the app devs and they're looking at it now so hopefully this gets fixed)
The heading of the image says "Same event, same selectors, with and without jQuery's :last" Under it shows two flame charts from Chrome. One takes 616ms and is the click event with :last in the selector list. The other takes only 16ms. It's the exact same event, but with :last removed.

ALT The heading of the image says "Same event, same selectors, with and without jQuery's :last" Under it shows two flame charts from Chrome. One takes 616ms and is the click event with :last in the selector list. The other takes only 16ms. It's the exact same event, but with :last removed.

Jun 8, 2023 · 2:40 PM UTC
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