Fixing CI for Node 4

[mansona]

I noticed that CI was broken on one of my other PRs #323 because apparently Yarn doesn't support Node 4

I'm not trying to open a can of worms with the whole "npm vs Yarn" debate, all I know is that CI is currently broken and this PR fixes the issue 👍

I also added testing in Node 8 and 10 for good measure 🎉

[LinusU]

I'm okay with switching to npm, what do you think @dylang? ☺️

[lorenzleutgeb]

I just proposed similar changes in #351 and #352. I didn't touch lockfiles, however. @mansona maybe you could update your PR by also including Node 12 which has since been released and is now the most current LTS.

[mansona]

@lorenzleutgeb I have updated the PR as requested. I haven't removed the old node versions that are EOL right now (4 and 6) because that would require a major version bump of npm-check

If this passes we can at least get it merged and then decide to drop node 4 and node 6 support later 👍

[lorenzleutgeb]

Not sure if removing a testing environment from build automation constitutes a breaking change. No interface to the outside world is being changed. But I get your point that it would be more diligent to test with Node 4 as well :)

Now let's hope some maintainers are around...

[mansona]

I am part of one of the Ember core teams and we have a policy that when you stop testing a particular version you're dropping support for that version. Essentially if anyone adds a small change (like arrow functions) you won't notice that it breaks the build in Node 4 because you're not testing it anymore 😄 It's why I wanted to fix CI in the first place so that it was still a clear intent of versions that you want to support 👍

[mcmxcdev]

Agreeing with @mansona here, it is very common that JS libraries bump up a major version when they drop support for an older node version.

[LinusU]

Thanks!

[...] it is very common that JS libraries bump up a major version when they drop support for an older node version.

Yeah, this is definitely how it should be done 👍