Webpack 4 plugin support tracker

Webpack 4 has been released, breaking many loaders and plugins. This issue tracks the status of Webpack 4 support in our Webpack-related dependencies.

/www

Plugin/Loader	Support for Webpack 4	Installed in /www
autodll-webpack-plugin	✔ v0.4.0 Supports only Webpack 4	✘
extract-text-webpack-plugin	✘. Plugin superseded by https://github.com/webpack-contrib/mini-css-extract-plugin.	✘ To be replaced with mini-css-extract-plugin. Sample config
style-loader	✘ Support added in stale PR https://github.com/webpack-contrib/style-loader/pull/282	✘
stylelint-webpack-plugin	✘ https://github.com/JaKXz/stylelint-webpack-plugin/pull/140	✘
flow-status-webpack-plugin	Unsure. No issues, PRs, or peerDependencies package.json entry.
postcss-loader	Unsure. No issues, PRs, or peerDependencies package.json entry.
webpack-merge	Unsure. No issues, PRs, or peerDependencies package.json entry.
babel-loader	✔ v7.1.3	✔
cache-loader	✔ v1.2.1	✔
clean-webpack-plugin	✔ Likely, according to issue comments	✔
copy-webpack-plugin	✔ v4.4.0	✔
css-loader	✔ v0.28.10	✔
eslint-loader	✔ v2.0.0	✔
file-loader	✔ v1.1.10	✔
html-webpack-plugin	✔ v3.0.0. Support actually added in this fork, but merged back into the original repo. Not sure which we’re supposed to be using now.	✔
html-webpack-inline-source-plugin	✔ v0.0.10	✔
lodash-webpack-plugin	✔ Likely, with warnings fixed in this PR.	✔
optimize-css-assets-webpack-plugin	✔ v4.0.0. Supports only Webpack 4.	✘ Must be upgraded with Webpack
sass-loader	✔ v6.0.7	✔
script-ext-html-webpack-plugin	✔ v2.0.0	✔
uglifyjs-webpack-plugin	✔ v1.2.2	✔
url-loader	✔ v1.0.0-beta.0, and v1.0.0 released.	✔
webpack-dev-server	✔ v3.0.0. Supports only Webpack 4.	✘ Must be upgraded with Webpack
workbox-webpack-plugin	✔ v3.0.0	✘

/scrapers/nus

Plugin/Loader	Support for Webpack 4	Installed in /scrapers/nus
babel-loader	✔ v7.1.3	✔
babili-webpack-plugin	No issues other than this deprecation warning: Tapable.plugin is deprecated. Use new API on .hooks instead.	To be removed.
webpack-node-externals	Probably - no issues observed.	✔

[li-kai]

@taneliang awesome work tracking these, wow 🥇

[ZhangYiJiang]

I took a look at PostCSS loader. As far as I can tell the loader should be forward compatible. The tests won’t pass because of Webpack config changes, but after messing around it for a bit I got it to work with only changes to the tests (although I can’t be sure if the changes I made are correct). The loader source does not seem to use anything that is deprecated, except for an option which was not removed in 3 -> 4 and we don’t use anyway.