[wp-trac] [WordPress Trac] #32197: Twemoji script and editor expansion combo making editor ridiculously slow in some circumstances

[WordPress Trac]

#32197: Twemoji script and editor expansion combo making editor ridiculously slow
in some circumstances
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 Reporter:  Otto42        |       Owner:
     Type:  defect (bug)  |      Status:  new
 Priority:  normal        |   Milestone:  4.3
Component:  TinyMCE       |     Version:  4.1
 Severity:  major         |  Resolution:
 Keywords:                |     Focuses:
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Comment (by rowd1951):

 Replying to [comment:6 azaozz]:
 > This is a problem with the textarea resize function. On keyup it copies
 all content from the textarea to a hidden div, then calculates the div
 height and sets the textarea height. For a long post that can become very
 slow.
 >
 > Now this is amplified by the emoji replacement. Adding the content to
 the hidden div triggers re-parsing of the whole content.

 Hi @azaozz, I submitted my own ticket relating to the manifestation of
 this problem as it appeared for me, here:

 https://core.trac.wordpress.org/ticket/32196

 For me, the post in text mode could be extremely long - say, 16,000 words
 (not characters) of lipsum, and I wouldn't experience any delay.

 I '''only''' experience a delay when I put in, say, a single bullet point
 or a curly quote among those 16,000 words.

 As soon as that character is deleted, text editor works like a charm
 again, with no lag whatsoever.

 However, your comment seems to suggest that this bug would lead to a lag
 when typing any text into a long post, but for me this isn't the case,
 it's '''only''' when a non-standard character is present among a lot of
 text.

 Could you explain what it is about, say, a bullet point or a curly quote,
 for instance, that has such a terminal effect on lag? When normal
 characters don't?

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Ticket URL: <https://core.trac.wordpress.org/ticket/32197#comment:8>
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