Live-blogging Marijn Haverbeke, creator of CodeMirror, at Full Frontal.
ACE - formerly Bespin - was faster and more portable, making CodeMirror look bad! So CodeMirror 2 is a rewrite based on some of those techniques.
Some performance tricks:
- Indexes both by line number and by vertical offset.
- Only renders the portion of the DOM you can see, plus a little on either side in case you scroll just a few lines.
- Selections are passed back to the original text area.