Nolan LawsonApr 23, 2017

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

Show threadNolan LawsonApr 23, 2017

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 BublΓ© too but those just feel off the table given all the JSX/spread/rest/decorators fanciness. Feeling like a JS curmudgeon here. #MastodonPerf

Show threadNolan LawsonApr 23, 2017

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

Show threadNolan LawsonApr 23, 2017
Anyway enough complaining. The goal here is to help make things better and not just tell these kids to get off my damned lawn. Back to reading about how Babel plugin order works and how to debug which plugin needs which other plugin. πŸ˜… #MastodonPerf
Show threadNolan LawsonApr 23, 2017
OK, I take back what I said. I am a moron. The source of the error was Uglify, which of course doesn't support ES6. 🀦 I'm back on track, working on my "slimmer JS bundle for modern browsers" PR. #MastodonPerf
Show threadNolan LawsonApr 23, 2017
Actually I take back my take-back. Trying to string together Rollup and Browserify and Babel with about 20 different plugins to handle JSX correctly and I'm starting to get a taste of why backend folks smack-talk modern JS practices so much. Some of these things are configured in 3 different places and it's hard to tell which config is actually winning. I get an error message and it's impossible to tell which plugin/transform/package caused it. We've ruined JavaScript, folks. #MastodonPerf
Show threadNolan LawsonApr 23, 2017
So unfortunately I haven't managed to trim a single byte from the Mastodon JS bundle yet, but on the bright side I am drinking again, so there's that. #MastodonPerf
Show threadNolan LawsonApr 23, 2017
All right, I wanted to accomplish at least one thing this weekend, so here's a PR to simplify the Babel configuration to make it less confusing: https://github.com/tootsuite/mastodon/pull/2377 #MastodonPerf
Show threadNolan LawsonApr 23, 2017
Seriously though I am just trying to configure Rollup to do ES6 module-inlining on the codebase and this error has a cutesy little emoji, but I have no idea what's causing it or how to fix it. I literally can't even tell if it's rollup, rollup-plugin-babel, babel, or some babel plugin that is causing the error. I just want Rollup/Babel/whatever to ignore jQuery since it's defined globally anyway. #MastodonPerf
Show threadMaiyannah BishopApr 23, 2017
@nolan This is the kind of stuff that backend devs like me cry into our C++ textbooks about.
Show threadNolan Lawson

@maiyannah The thing is, I'm deeply embedded in this community: I've written Browserify transforms and Rollup plugins, and I personally know many of the folks who maintain Babel, Rollup, Webpack, etc. And yet even *I'm* a bit baffled trying to navigate this codebase.

This feels kinda like Perl, where every time you look at a new codebase you might as well be looking at an entirely different language. Wondering how much I've contributed to this situation. πŸ˜•

Apr 23, 2017 at 11:52pmWeb
Show threadMaiyannah BishopApr 23, 2017
@nolan Oh yeah, there's definitely good JS and such out there, it's just, when we complain about javascript being a bit rubbish?  Yeah, THIS is what we're talking about.  It gets convoluted really quickly and I sometimes wonder if even the people who developed it really understand it.
Show threadNolan LawsonApr 24, 2017
@maiyannah We don't. We really don't. I work for a browser vendor and I've written over 100 npm modules and I've been doing JS for years and yet here I am researching what `babel-plugin-transform-decorators-legacy` is and why there's a legacy version and why we need this thing in the first place. πŸ˜•
Show threadMaiyannah BishopApr 24, 2017
@nolan "Maiya, why are you taking like three months pre-release to document everything?"

Basically, because this.
Show threadAntoine AflaloApr 24, 2017

@nolan @maiyannah move fast and break thing mentality.

Backward compatibility doesn't matter .πŸ˜•

Show threadNolan LawsonApr 24, 2017
@maiyannah There is nothing wrong with JavaScript itself; it's a pretty dang good language as evidenced by the fact that it powers this beautiful thing called the web, but because it's the #1 language in the world, it has a lot of different philosophies and fiefdoms and interests and they all kind of clash and conflict with each other at the same time.
Show threadMaiyannah BishopApr 24, 2017
@nolan Except that true is false, anyways ;)
Show threadNolan LawsonApr 24, 2017
@maiyannah Bah, that's what linters are for. πŸ˜‰
Show threadJeremiah "CaptainKraft" GoerdtApr 24, 2017
@maiyannah @nolan 749 trillion devices use Java. Doesn't make it good πŸ˜‹
Show threadMarcin CieΕ›lakApr 24, 2017
Great thread by @nolan @maiyannah
cc @jsilvax