Update for Elm 0.19

[xtian]

Fixes #148

[xtian]

rtfeldman/node-elm-compiler@9a12354#diff-168726dbe96b3ce427e7fedce31bb0bcL12

[klazuka]

What’s the status on this PR? Is it just on hold until support for 0.18 can be dropped?

I ask because I’m working on 0.19-compatible hot reloading based on fluxxu/elm-hot-loader, and one of the last remaining things to do is ensure that it can plug into webpack’s HMR API. If this PR is ready from a technical perspective, then I will go ahead and develop against this branch/fork.

[xtian]

@klazuka As far as I have tested it is ready from a technical perspective.

[klazuka]

@xtian I integrated your branch today. The code itself worked fine (thank you!), but some of the docs/examples are out-of-date. Here are the list of changes that I had to make to get things working:

webpack options

• pathToMake has become pathToElm
• warn is no longer support by the Elm compiler nor node-elm-compiler

various things in the example-wp4 directory

(presumably similar problems exist in wp2)

• replace elm-package.json with elm.json
• index.js does not initialize the main Elm module correctly (it uses embed, but it should use init)
• index.js should import the Elm app as const { Elm } = require('./Main.elm');, otherwise it gets double-wrapped and you need to do Elm.Elm.Main.init

various other things

• package.json at the root installs Elm 0.18 locally (no good alternative for this now, but noting it so that it gets done when 0.19 is published publicly)
• test/loader.js still references elm-package.json on line 11

[xtian]

@klazuka Ah yes, sorry I should have noted that the changes on the app side can be viewed here: halfzebra/create-elm-app#256

Glad it worked for you! :)

[klazuka]

No problem. But that PR only addresses the app-side in create-elm-app. There's a lot of docs/readmes/examples in this repo that also need to be updated. Probably should be done in a separate PR. Just pointing it out here so that it doesn't slip through the cracks.

[xtian]

@klazuka Yep, I am waiting until I get some response to this PR before diving into updating the documentation.

[xtian]

ping @rtfeldman @eeue56

This is ready for review

[klazuka]

@xtian good news, the npm installer for 0.19 was released this morning. Now you can do npm install elm@rc1 to get 19. Could you please update the Elm dependency in package.json so that it no longer refers to 0.18? My hot-loader project depends on your branch, and the 0.18 dependency is causing a conflict. Thank you!

[xtian]

@klazuka Updated :)

[Punie]

@xtian I think an option for optimize: true should be added to provide the new --optimize flag from elm make.
Otherwise, I just tested your PR on my own project alongside @klazuka 's elm-hot and it works like a charm, thanks 👍

[hecrj]

I tried this branch. It seems that live reloading doesn't work when saving imported modules.

It looks like find-elm-dependencies needs to be updated so it looks for elm.json instead of elm-package.json. Then node-elm-compiler, which uses it, will need to update the dependency (and probably support the new --optimize flag, as @Punie said).

I have made a dirtyfix for myself in the meantime here: https://github.com/hecrj/elm-webpack-loader/tree/0.19

[xtian]

@hecrj Awesome, thanks for posting a fix!

I don't have the bandwidth to tackle PRs for those projects right now so if someone else wanted to do that it would be very cool.

[eeue56]

PRs for both of those repos would be very welcome!

[Punie]

If @hecrj is willing to move his fixes to PRs on those repos. If he doesn't have the time, I can try to takle this when I get home in the evening.

[Edit]: I made those PRs (as far as I could tell, the changes needed were pretty minimal, but I might have missed something. I saw that progress towards 0.19 was already made on node-elm-compiler which lacked only the --optimize flag and the upgraded version of find-elm-dependencies)

[razzeee]

Can we maybe not hard remove pathToMake and warn and instead show an error pointing to the reason or a deprecation notice?

[eeue56]

@razzeee This release will break anyway, so I'm not sure if we can do that. Better to have a hard error and send people here to pin to the 0.18 version.

Just waiting on one last PR to be merged, then we're good to go with this release

[razzeee]

Well the hard error you get at the moment is quiet unhelpful. That's the whole reason I reached out. I think we can do much better, otherwise you will have people asking here regularly.

[rtfeldman]

I like the idea of keeping them for this release, and having them immediately bail out with a helpful error if you use them. 👍

[rtfeldman]

We ended up with some interesting experimental Uglify results in a discussion with @Punie on Slack that I thought I'd share here: ("two step version" refers to running Uglify twice, first with --compress and then again with --mangle - see the elm-spa-example README for why this helps)

So the overall best (for elm-spa-example at least) still seems to be running uglify-js twice (once with --compress and then again, separately, with --mangle) with passes=2. Second best is running uglify-es once with passes=3. Everything else did the same or worse than those two configurations.

Assuming it's too much of a pain to get Webpack to run Uglify twice, it seems like the best Uglify config for Webpack might be:

• Use uglify-es over uglify-js
• passes=3
• both --compress and --mangle enabled at once

[Punie]

Just to add to @rtfeldman comment: it seems that uglify-es is the default minifier used by the UglifyJS Webpack Plugin for Webpack 4 (see webpack-contrib/uglifyjs-webpack-plugin) so the following configuration should suffice :

new UglifyJsPlugin({
  uglifyOptions: {
    compress: {
      pure_funcs: ['F2','F3','F4','F5','F6','F7','F8','F9','A2','A3','A4','A5','A6','A7','A8','A9'],
      pure_getters: true,
      keep_fargs: false,
      unsafe_comps: true,
      unsafe: true,
      passes: 3
    }
  }
})

I don't know about webpack 2 and 3 though.

[eeue56]

@rtfeldman / @Punie can you share those somewhere else rather in this PR? 🙏 Maybe a separate PR with uglify tips?

[eeue56]

Released as 5.0.0. Thanks!