Update: Eslint to 3.0 and update CI builds (fixes #4638)

[gyandeeps]

Q	A
Bug fix?	no
Breaking change?	no
New feature?	no
Deprecations?	no
Spec compliancy?	no
Tests added/pass?	no
Fixed tickets	#4638
License	MIT
Doc PR	reference to the documentation PR, if any

Update ESLint to 3.0 and make sure lint is only run under nodejs version greater than 4 (run on latest).

Questions:

Lint has 2 errors.

babel\packages\babel-cli\src\babel-doctor\rules\deduped.js
  1:16  error  This generator function does not have 'yield'  require-yield

babel\packages\babel-cli\src\babel-doctor\rules\has-config.js
  4:16  error  This generator function does not have 'yield'  require-yield

✖ 2 problems (2 errors, 0 warnings)

@hzoo any idea what should i do with these errors? (asking bcz I dont have a good idea abt the code base yet 😄 )

[hzoo]

awesome @gyandeeps!

that's interesting because https://github.com/babel/babel/blob/master/packages/babel-cli/src/babel-doctor/rules/deduped.js is using async functions? dono if the rule is wrong or something

config is https://github.com/babel/eslint-config-babel/blob/master/index.js

[hzoo]

i'd be ok with just turning off the rule for those files/lines - made #4678 to remove it anyway.

But yeah should investigate why it's saying that for async functions (possibly just babel-eslint issue as well)

[gyandeeps]

how about for this PR, i just turn this rule off inline for those 2 cases?
Also is this what you expected from this PR?

[hzoo]

Yep that's fine!

[gyandeeps]

Done.

its a babel-eslint issue, it sets the generator: true on the AST node.

[hzoo]

Weird since it shouldn't be doing that anymore babel/babel-eslint@1823b5e

[ljharb]

this will run the tests even in the linter run - i think you want if [ -z "${LINT-}" ] here to skip this.

[gyandeeps]

I can do this. This way it will be fast as that build will only do lint.

[ljharb]

Exactly :-)

[hzoo]

I wonder if we can skip npm install in that case (not that it would matter much)

[ljharb]

nope, you need it for eslint

[hzoo]

awesome stuff! 🎉

[hzoo]

Ok I was investigating and it's because of eslint-config-babel

└─┬ eslint-config-babel@1.0.1
└── babel-eslint@6.1.2

So it's still using the old babel-eslint