Replace MathJax with KaTeX

[davidar]

KaTeX is much faster, but MathJax is more mature. Need to evaluate when it will make sense to switch. A hybrid approach could be possible in the short-term.

• http://www.intmath.com/cg5/katex-mathjax-comparison.php
• http://www.intmath.com/blog/mathematics/katex-with-asciimathml-input-and-mathjax-fallback-9456

CC: @jbenet
Blocked by: KaTeX/KaTeX#61

[rht]

The math envs in arxiv corpus can be a specimen to compare the coverage of KaTeX vs MathJax.

[davidar]

@rht Yeah, that's what I was thinking too, so we'll delay making a decision on this until arXiv+TeX.js gets going

[rht]

The state of KaTeX vs MathJax on sep 16 2014:
http://meta.math.stackexchange.com/questions/16809/a-mathjax-alternative-from-khan-academy
~250 vs ~800

'Current' (resolved to oct 28 2015) state:

$ curl https://raw.githubusercontent.com/wiki/Khan/KaTeX/Function-Support-in-KaTeX.md | grep '\\' | wc -l
271

Mathjax, http://docs.mathjax.org/en/latest/tex.html#supported-latex-commands (https://ipfs.io/ipfs/QmVGLiCbhV6GYEngAJrR3F19tCxgfmz9Nod3FdNBPafZ1W), has 778 commands, 481 if AMS* and non-standard are excluded.

271 vs 481-778.
I suppose because it is currently tailored specific to Khan Academy's usage (instead of arxiv).
There is no explicit roadmap for feature parity with mathjax that I know of.

[Axure]

└─[$]> curl https://raw.githubusercontent.com/wiki/Khan/KaTeX/Function-Support-in-KaTeX.md | grep '\\' | wc -l
564

as of 2016.10.11