Elm Optimize

NOT FOR SHARING YET - Please wait for the announcement before sharing widely, it should be coming soon :)

Note, Experimental - This project is just starting. While we currently believe every adjustment to the resulting javascript should be safe and make things explicitly faster, it's hard to be 100% certain until we have a large number of projects using it successfully. So, beware!

And let us know how it goes by leaving a comment in this issue. 😃

Elm is fast.

Can we make it faster?

Turns out, yes! 🚀

Elm Optimize is a project for exploring different optimizations that are specific to elm-generated javascript.

There are two parts to this.

1. Explore different javascript representations for Elm code. This means gathering data on what a given representation would mean on realworld projects, and across browsers.

2. A tool you can use right now to compile elm using the adjustments that have given us the most speed!

Note This work was given a massive headstart by Robin Heggelund Hansen's article on areas where the Elm Compiler's output could be improved. Go read it! It's great.

Installation and Usage

npm install -g elm-optimize

Then you can use elm-optimize just as you would elm-make --optimize.

elm-optimize Main.elm

will generate an elm.js file.

The only configurable option is what to name the generated js file.

elm-optimize Main.elm --output app.js

Note — elm-optimize only generates a js file, it doesn't support generating HTML.

Another Note — Before deploying your app, you should also minify it and gzip it. elm-optimize does not do that for you. Check out this doc for a recommended setup.

What's actually happening?

This might seem a bit like magic. ✨

If you're interested in getting to know what's happening, here's an overview of all the JS transformations we are exploring!

Not all of them are included in the CLI tool because not all of them turned out to be beneficial. Part of this endeavor is a science project :bowtie:, where we capture data so we can know which transformations turn out to be worthwhile.

A few are listed there as either incomplete or not attempted. That's future work!

Benchmarks

Note — These results are really exciting! However, it's not totally obvious that your project will see similar gains. Performance is a tricky beast! If you do see significant speedups in your project, leave a comment here on this issue, we love to see realworld cases.

In an effort to quantify these transformations, we've put together a number of benchmarks, including some from exisiting Elm packages such as dillonkearns/elm-markdown, w0rm/elm-obj-file, and mdgriffith/elm-ui.

Our goal is to have benchmarks that track performance on code where performance is meaningful.

Here's the most recent, comprehensive run of the benchmarks.

Though here are a few highlights:

Note — keep in mind that these numbers have all the caveats that benchmarks usually have. You may not see similar numbers depending on your machine, your browser, subtle differences in your code, etc.

Another Note — From what we've seen, given that you're minifying and gzipping your JS, these transformations should either have no effect on asset size, or may even make your app slightly smaller.

Html

Name	Transformtions	Browser	Ops/Second	% Change
create a 4 level nested html tree	baseline	firefox	19,878
create a 4 level nested html tree	optimized	firefox	24,878	(125%)
create a 4 level nested html tree	baseline	chrome	43,689
create a 4 level nested html tree	optimized	chrome	113,266	(259%)

Elm Markdown

Name	Transformtions	Browser	Ops/Second	% Change
dillonkearns/elm-markdown	baseline	firefox	1,226
dillonkearns/elm-markdown	optimized	firefox	2,497	(204%)
dillonkearns/elm-markdown	baseline	chrome	3,116
dillonkearns/elm-markdown	optimized	chrome	5,099	(164%)

Running Benchmarks Locally

1. Clone this repo
2. Run npm install
3. Run npm run report and a simple benchmark will hopefully run and print results to the terminal.

Note you can control which benchmark runs with which transformation by adjusting src/benchmarks/run.ts.

Contributing

For this project, contributions always start with communication before code!

That being said, there are a few areas that might be opportunities for contribution.

First and formost is to try elm-optimize on any current Elm project you have.

We'd love to hear your results whether they be success, no effect, or caused a regression.

If your project saw an explicit improvement or performance regression, leave a comment on this issue.

For more serious issues, feel free to file a separate issue.

Secondly, if you believe there are public benchmarks that we could track that are not essentially covered by our current benchmarks, let us know! We want the benchmarking suite to be as comprehensive as possible, though we have to weigh that against having a million benchmarks that essentially test the same thing.

Thirdly, if you believe there are additional JS transformations that would be interesting to explore, or would like to try improving existing transformations in some way, get in touch!