Webpack 4.0

[gauravtiwari]

This PR adds webpack 4.0 support to Webpacker.

TODO:

• Use new webpack 4 development and production modes
• Upgrade webpack dev server
• Pre-release of WebpackManifestPLugin compatible plugin
• Mini css extract plugin
• Vue loader
• Use new built-in options
• Update readme
• Test examples

Blockers

• Improve webpack 4 support (afterEmit issue) shellscape/webpack-manifest-plugin#128
• HMR support in mini-css-extract-plugin
• Vue loader #1196

[renchap]

It might be a good idea to replace extract-text-plugin with https://github.com/webpack-contrib/mini-css-extract-plugin once HMR support is merged.

[gauravtiwari]

Thanks @renchap that's the plan 👍

[montogeek]

What is the status of this PR? Is there something we can help from webpack side?

[rossta]

@montogeek Note the blocker in the description. This project relies on plugin that hasn't merged v4 support yet.

[montogeek]

@rossta Already commented on it

[montogeek]

This won't work with ES6 modules

[gauravtiwari]

This PR is going to take a while since the plugin and loader support isn't 100% yet - the main blockers are manifest and vue loader, everything else seems to be working fine.

Will release a beta once this PR is merged and then we can incrementally enhance in separate PRs until stable 4.0.x

[gauravtiwari]

Just published a pre-version:

To try out:

gem 'webpacker', '>= 4.0.x'

yarn add @rails/webpacker

[apuntovanini]

@gauravtiwari any hints on how to get it working / upgrading?
Thanks!

[gauravtiwari]

@apuntovanini Pretty simple and no breaking changes (AFAIK) - just update gem and npm package as above ^^

[saneef]

@apuntovanini You might have to run bundle exec rails webpacker:install if you are upgrading on the existing project.

[apuntovanini]

:) yep, thats the reason I asked, mine is broken, saying no manifest found. I use CommonsChunkManifest (now deprecated, isn't it?), but even without it doesnt work

[apuntovanini]

ah, I see, didn't try that, I will try again and let you know ASAP, thanks!

[gauravtiwari]

@apuntovanini Oh yes, that's true. Please see this gist on how to migrate common chunk - https://gist.github.com/sokra/1522d586b8e5c0f5072d7565c2bee693#configurate-cache-groups

[gauravtiwari]

With webpacker it would be,

environment.config.merge({
  optimization: {
    splitChunks: {
      cacheGroups: {
        commons: {
          test: /[\\/]node_modules[\\/]/,
          name: 'vendors',
          chunks: 'all'
        }
      }
    }
  }
})

[apuntovanini]

Wonderful, it does work (bundle exec rails webpacker:install was indeed needed)! Now running webpack 4 with no issues! Thanks a lot!

[JWesorick]

when is the non pre release version coming?

[vcavallo]

I see webpack: ^3.11.0 in my yarn.lock - is that correct? I was

[danielpowell4]

@gauravtiwari Any timeline for moving 4.x to stable?

If there is a clear checklist/roadmap I'm sure there are a good few of us who will help out!

[gauravtiwari]

@danielpowell4 Thanks, basically it's nearly there. I have made this PR (#1546) a while ago but couldn't finish it, apologies :(

Will try to get this done over the weekend and see if I can publish a stable release next week.

[danielpowell4]

@gauravtiwari no need to apologize! Timeline sounds awesome.

I have been on the pre version since it came out. Only recently ran into a snag when I went to tweak my babel config.

If you need help writing docs or monitoring the repo, feel free to reach out!

[iChip]

What's involved in getting 4.x released? Happy to assist.

[danielpowell4]

@gauravtiwari Any updates?

I'm sure some like @iChip are willing to lend a hand if possible!

[gauravtiwari]

Hey, Sorry, I need to find sometime to review some PRs like: #1694 and go through this big list of issues: https://github.com/rails/webpacker/issues to see if we have missed anything obvious that should be in 4.x stable release.

What if I release a beta 4.x version? Would that help time being?

[gauravtiwari]

Just made another pre-release:

yarn add @rails/webpacker@next
bundle update webpacker

[gauravtiwari]

Also, now Rails 6.0-alpha ships with Webpacker as default- https://github.com/rails/rails