Roadmap for version 4

[haoqunjiang]

It's time for a major version bump.
This will be a relatively small release but will include a number of necessary breaking changes.

Planned Features

Dependency Updates

• webpack-chain v5 (feat!: upgrade to webpack-chain v5 #3913) CHANGELOG
• css-loader v2 (feat!: upgrade css-loader to v2 #3866) CHANGELOG
• copy-webpack-plugin v5 CHANGELOG (a very subtle change, unless you've touched its options in config there won't be any affect)
• Nightwatch v1 (chore(plugin/nightwatch): bump nightwatch dependency #3388) MIGRATION GUIDE
• Use ESLint v5 by default (feat!: use ESLint v5 by default everywhere #3775) (projects scaffolded with Vue CLI 3.1+ are already using it, for those scaffolded by 3.0.x, here's the migration guide for eslint and release note of eslint-plugin-vue v5)
• Jest v24 (feat!: upgrade jest to v24 #3870) RELEASE NOTE
• workbox v4 (feat!: upgrade to workbox v4 #3915) RELEASE NOTE and MIGRATION GUIDE
• core-js 3 (#3912) (It's an internal change of @vue/babel-preset/app, for now we use core-js 2 by default, babel 7.4.0 supports core-js 3, once we upgraded core-js, some undocumented public APIs may change)

Changed Behavior

• vue-template-loader: preserveWhitespace: false -> whitespace: 'condense' feat!: set whitespace: 'condense' for template compiler #3853
• use NODE_ENV=production by default if not specified when running vue-cli-service build feat!: set default NODE_ENV to production when running build command #3859
• plugin-pwa: manifest.json should be generated during the build process rather than scaffolding feat!: manifest.json should be generated by cli-plugin-pwa #2981

New Features

Most proposed new features other than plugin APIs can also be landed in v3.x so they are not listed here.

• Plugin API: Allow plugins to provide a minimum vue-cli version feat: add .version field and assertVersion helper to plugin api #3861
• vue upgrade overhaul, allowing running codemods from plugins
• Plugin ordering Hook to act after others plugins invocation #1754, Plugin depending on another plugin #1938

Removed

• Drop Node.js v9 support (in documentation, no need to touch the code)
• remove support for vue-cli-service e2e command (already deprecated since 3.0 rc) (chore: remove support for legacy vue-cli-service e2e command #3774)

Needs Discussion

• Drop unit mocha in favor of Jest only
  • Mostly because mocha-webpack is unmaintained and unlikely to work with webpack 5
  • Need good migration strategy for existing users
• Use mochapack instead of mocha-webpack
• Upgrade to mocha v6

How Can I Help?

Please let us know your thoughts and if we missed anything.
We'll be more than happy to explain our rationale around these decisions if there's any further questions.

If there's anything you (and the community) feel strongly about but is not found on this list, please make an effort to send a PR!
We'll be more than happy to accept contributions.

[edimitchel]

Mocha is much faster than Jest. Keep it.

[NeiPCs]

Yep, since we know what breaking changes will apply, we can work on documentation of migration from X to Y version.

[LinusBorg]

Mocha is much faster than Jest. Keep it.

We would, if someone can assure us mocha-webpack will continue to work with webpack 5 even though it's currently unmaintained.

Otherwise we just keep a feature alive that is destined to die soon anyway.

[salvadordiaz]

There is a fork of mocha-webpack that works with webpack 4 and mocha 4, 5 and 6:
https://github.com/sysgears/mochapack

I really hope that we can avoid having to migrate our test suite from mocha to jest.

[Garito]

My 5 cents: the simpler the better

[LinusBorg]

@salvadordiaz That looks promising, assuming the author is up to upgrade it to webpack 5 compatibility when that time arrives.

[geedew]

Is there a discussion ticket for the Codemods work?

[LinusBorg]

Nope. Also, we should probably do a real RFC for his as the vue-cli repo is one of the repos we included for the official RFC process in https://github.com/vuejs/rfcs#when-to-follow-this-process

We might discuss possibly deprecating mocha there as well, as it's likely a hot topic.

[yannick-milanetto]

Is there any plans to support server-side rendering in core, without having to go for a 3rd party plugin ?

[larixer]

@LinusBorg Hi, I'm the maintainer of mochapack. Is Webpack 5 support is the only thing you need to continue using mocha unit tests and mocha-webpack, or have you made a decision to drop mocha tests in favor of jest already?

[LinusBorg]

@Vlasenko Hi 😁

We haven't made that decision, that's what this issue is meant to discuss.

We don't want to "get rid" of mocha. Until someone mentioned your fork, we just didn't see any future for it since mocha webpack was unmaintained.

So if you ate panning to keep on working on mochapack and make it work with webpack 5, my opinion would be to keep it 🙂