Add node/no-unsupported-features rules and fix unit tests

[pvdlg]

Fix #108

The following rules are added, only if the node-version is used or if the package.json has a valid engines.node prop:

• node/no-unsupported-features/es-builtins
• node/no-unsupported-features/es-syntax
• node/no-unsupported-features/node-builtins

[pvdlg]

@sindresorhus it seems the repo is not activated on Travis anymore. Maybe the orga has been migrated to travis.com?

[sindresorhus]

This is a great addition, I'm just reluctant to merge it because it's going to cause a lot of problems for me. I use async functions with AVA in lots of tests (that are transpiled), even though the module targets Node.js 6. Can we {ignore: ['asyncFunctions']} for now?

This is what I'm seeing everywhere:

  ✖    7:45  Async functions are not supported until Node.js 7.6.0. The configured version range is >=6.0.0.  node/no-unsupported-features/es-syntax
  ✖   20:43  Async functions are not supported until Node.js 7.6.0. The configured version range is >=6.0.0.  node/no-unsupported-features/es-syntax
  ✖   46:27  Async functions are not supported until Node.js 7.6.0. The configured version range is >=6.0.0.  node/no-unsupported-features/es-syntax
  ✖   53:38  Async functions are not supported until Node.js 7.6.0. The configured version range is >=6.0.0.  node/no-unsupported-features/es-syntax
  ✖   62:71  Async functions are not supported until Node.js 7.6.0. The configured version range is >=6.0.0.  node/no-unsupported-features/es-syntax
  ✖   71:42  Async functions are not supported until Node.js 7.6.0. The configured version range is >=6.0.0.  node/no-unsupported-features/es-syntax
  ✖   80:62  Async functions are not supported until Node.js 7.6.0. The configured version range is >=6.0.0.  node/no-unsupported-features/es-syntax
  ✖   89:68  Async functions are not supported until Node.js 7.6.0. The configured version range is >=6.0.0.  node/no-unsupported-features/es-syntax

[sindresorhus]

it seems the repo is not activated on Travis anymore. Maybe the orga has been migrated to travis.com?

It's not migrated, but I've had this issue on other repos too. Probably just another Travis bug. I've tried to reactivate the repo now, but I don't think it takes effect on existing PRs...

[pvdlg]

This is a great addition, I'm just reluctant to merge it because it's going to cause a lot of problems for me. I use async functions with AVA in lots of tests (that are transpiled), even though the module targets Node.js 6. Can we {ignore: ['asyncFunctions']} for now?

Now that you mention that, it might create other issues unless you use override to specify that everything under test should use nodeVersion: >=10.

The proper fix would be to detect AVA files and put them in an override with nodeVersion: >=10.
I think I tried that in a78e02e but we stopped as we didn't find a solid way to detect AVA files.

Maybe I can split this PR in two:

• 1 to fix the test
• 1 to add node/no-unsupported-features that we can merge later once we have a solution for AVA files

[pvdlg]

See #344

[sindresorhus]

I think I tried that in a78e02e but we stopped as we didn't find a solid way to detect AVA files.

Was there a PR for this with a discussion? Link?

[pvdlg]

Yes: #281

[sindresorhus]

I think this feature is pretty valuable. How about we do {ignore: ['asyncFunctions']} for now and merge this and then open an issue about enabling it when we have a solution for AVA?

[pvdlg]

I think this feature is pretty valuable. How about we do {ignore: ['asyncFunctions']} for now and merge this and then open an issue about enabling it when we have a solution for AVA?

I don't think it's a good idea, because even if asyncFunctions is the most common case you will have many other features/API that will be problematic.

Maybe we could just set nodeVersion to 10 for the typical AVA directory and explain in the doc that if you have any directory with files that will be transpiled (with Babel or non-default AVA directory) you have to set nodeVersion in an override for that directory. That applies only if you set engines.node in your package.json

[sindresorhus]

Good news. AVA no longer includes Babel by default. https://github.com/avajs/ava/releases/tag/v3.0.0

[pvdlg]

Removed that test as this case can never actually happens as the validity of the semver range is verified earlier in mergeOptions

[pvdlg]

@sindresorhus I updated the PR and clarified the doc regarding transpiled code.

If you have a codebase that targets two different Node version (as it was the case with AVA) then you will need to define an overrides to avoid having the new rules reporting error.

But any case it's a good practice to define such overrides as it would enable more rules for your source (non-transpiled) code such as unicorn/prefer-flat-map, no-useless-catch, prefer-object-spread etc...

[sindresorhus]

But any case it's a good practice to define such overrides as it would enable more rules for your source (non-transpiled) code such as unicorn/prefer-flat-map, no-useless-catch, prefer-object-spread etc...

👍

[sindresorhus]

Awesome to be able to finally merge this 🙌