[wp-trac] [WordPress Trac] #58472: Emoji loader script causes ~100ms long task

[WordPress Trac]

#58472: Emoji loader script causes ~100ms long task
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 Reporter:  westonruter   |       Owner:  westonruter
     Type:  defect (bug)  |      Status:  accepted
 Priority:  high          |   Milestone:  6.3
Component:  Emoji         |     Version:  4.2
 Severity:  normal        |  Resolution:
 Keywords:  has-patch     |     Focuses:  javascript, performance
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Comment (by flixos90):

 I've conducted another benchmark with the latest version of the PR, just
 to double-check that it's still as impactful as previously envisioned
 (since several changes have been made in the last 2 weeks). Happy to
 report that it is!

 Since the last benchmark, the `benchmark-web-vitals` command line tool now
 also reports "LCP minus TTFB", which is the most meaningful metric to look
 at in order to assess the performance impact of this change. In that
 metric, the performance improvement is **56ms / 45%**!

 Overall LCP improvement based on the new metrics is ~30%, however that is
 skewed by TTFB being faster in the test runs for this PR, so it's not
 ''that'' much in reality. If we add the baseline TTFB of ~150ms back to
 the median "LCP-TTFB" result, we see a **~20% overall LCP improvement** -
 somewhat of an overall estimation with cleanup of the TTFB inconsistency.

 **TLDR: This is an amazing performance win.**

 [https://docs.google.com/spreadsheets/d/1U72tibGU3rpxiH_2A6gBiZUIU7OXSkKjG2bIsDACqWs/edit#gid=1373034582
 See the full results here]

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Ticket URL: <https://core.trac.wordpress.org/ticket/58472#comment:23>
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