I've always been skeptical of the JS community's mania for Babel plugins and compile-to-JS languages, and honestly, working with the Mastodon codebase and trying to shrink a 2.6MB JS bundle, I feel like my worst fears have been realized.
I've decomposed all of Mastodon's Babel presets into these plugins. If I remove a single one, I get some inscrutable error apparently caused by some other plugin in the pipeline. Feels like a big Jenga tower. 😞 #MastodonPerf
In my ideal world, we'd have two bundles:
1. ES6 without polyfills (for modern browsers)
2. ES5 fallback (using a "cut the mustard" test like fetch+Object.assign+etc.)
At this point I can't even figure out what the savings would be for #1 vs #2 because I can't get the codebase to compile *without* the Babel transforms. I wanted to try Rollup and/or Bublé too but those just feel off the table given all the JSX/spread/rest/decorators fanciness. Feeling like a JS curmudgeon here. #MastodonPerf
Like, in 99.9% of my JS projects I use vanilla ES5 and *maybe* ES6 modules, but only because then I can use Rollup to compile down to the smallest possible JS, which I then ship to consumers.
Performance is a top priority for me, and I just don't feel like syntactic sugar like arrow functions, template strings, const/let, etc. are so important that it's worth shipping a bunch of polyfills and transpiler bloat to my consumers. But I feel like I'm in the tiny minority on this one. #MastodonPerf
Nolan Lawson
Darryl Pogue