text-unicode VS codejar

We had to handroll our own OT implementation inhouse (based on https://github.com/ottypes/text-unicode) since we had built the system for it already. I suspect we would've used or forked CodeMirror's collab package if we were starting today.

Also huge fan of yjs, but the implementation is not compatible with codemirror 6, only version 5 (AFAIK)

Well said.

I've had a lot of conversations with javascript engineers over the years who've argued to me that well tuned JS will be nearly as fast as the equivalent C code. I've written plenty of little toy benchmarks over the years, and in my experience they're partly right. Well written JS code in V8 can certainly run fast - sometimes around half the speed of C code. But a massive performance gap opens up when you use nontrivial data structures. Nested fields, non-uniform arrays, trees, and so on will all cripple javascript's performance when compared to C's equivalent of simply embedding nested structs. If you couple clean C data structures with allocation-free hot paths from arenas, the performance of C will easily hit 10-20x the performance of the equivalent JS code.

From memory my plain text based operational transform code does ~800k transforms / second in javascript. The equivalent C code does 20M/second. The C implementation is about twice as many lines of code as the JS version though.

(The code in question: https://github.com/ottypes/text-unicode/blob/master/lib/type... / https://github.com/ottypes/libot )

FYI, this is a few months old, if you want to read something up to date, check out https://blog.replit.com/codemirror

Unfortunately copy and paste doesn't work well on Firefox on Linux in any of these fancy editors because support for the primary selection is broken and Mozilla doesn't seem interested in fixing it: https://bugzilla.mozilla.org/show_bug.cgi?id=1593761

The article calls CodeMirror "lightweight" but the minified JS is still over 1 MB. If you want lightweight then you probably want something like CodeJar (https://github.com/antonmedv/codejar) which clocks in at 2 kB.

CodeJar