^ Per T160061#3088481.

I've been researching mustache.js (canonical impl) and hogan.js (twitter's impl) and this is what I've found out:

• Mustache.js doesn't precompile templates.
  • It can precompile a token tree which is bigger than the source but there is no public API for consuming it.
  • You need the library both at precompilation and runtime (which we already ship).
• Hogan.js does precompile templates.
  • We use it in mobile, but not desktop (which already ships mustache).
  • The precompiled templates require of the library runtime
  • Patch: WIP: Precompile mustache templates to JS
    • It would add the Hogan.js runtime to the compiled assets
      • Seems wasteful given mustache is in core and this hogan compiler would end up duplicated with mustache or other parts of the system using hogan
    • The mustache templates can indeed be precompiled to JS
      • Difference in size doesn't seem to be big
      • The string is already parsed. Could be a perf improvement for mobile, doubt it will make a difference on desktop. Specially in this particular instance
      • The full hogan.js is included by mustache-loader, it could probably be tweaked to only include the hogan.js/lib/template.js for a smaller bundle size since templates are precompiled.

Because of this ⬆️,

• I don't think we should bundle the templates into the compilation step right now, in Page-Previews.
• This seems like it could be an improvement for a project like MobileFrontend where hogan is already used extensively.
• After review/discussion we should decline this task.

Moving to review.

Links:

• mustache-loader for webpack: https://github.com/deepsweet/mustache-loader
• WIP patch using ^: https://gerrit.wikimedia.org/r/#/c/347341/1
• Mustache.js API docs: https://github.com/janl/mustache.js#api
• Hogan.js docs: https://github.com/twitter/hogan.js

Change 347341 had a related patch set uploaded (by Jhernandez):
[mediawiki/extensions/Popups@master] WIP: Precompile mustache templates to JS

https://gerrit.wikimedia.org/r/347341

Change 347341 abandoned by Jhernandez:
WIP: Precompile mustache templates to JS

Reason:
Not following through with this. See T160058

https://gerrit.wikimedia.org/r/347341

Nice write up @Jhernandez 👊

Sounds reasonable. ෴

Thanks for the write up. Seems we learned a bunch. Declining is fine with me.
How do we want to go ahead with this for MobileFrontend? We have a lot of templates there so it would be good to get a sense of what the blockers are and how we envision that happening.

@Jdlrobson As it is right now, I don't have any doubts that precompiling in MobileFrontend will be a benefit. Hogan supports it, and if our tooling does, then we'll be sending smaller templates and doing less work in mobile devices. All pluses.