@tleunen The commit I did for my babel-preset (futagoza/babel-preset-futagozaryuu@64645b6) passed on Travis (Node.js v4, v6 and v8) using these changes, so I'm not sure why appveyor is complaining, but it seems to be throwing the same error as #236. Any suggestions/solution?

The problem is some dependencies (like Jest) don't support Node 4 in their most recent version (v22) because of jsdom. But we shouldn't really use jsdom in the first place. So try to set the testEnvironment option to node to see if node 4 passes.

We would also need to run node 4 on circle-ci (See config.yml)

But you mark a point. Since Node 4 is still in LTS until April 2018, we should definitely make sure we're still compatible with it.

Codecov Report

Merging #286 into master will not change coverage.
The diff coverage is n/a.

Set testEnviroment in package.json and updated .circleci/config.yml

Since Node 4 is still in LTS until April 2018, we should definitely make sure we're still compatible with it.

The fact that April is just a week away kind of makes this PR useless 😆, but even though LTS ends in April 2018, Node.js v4 will still be around for a while (at least I intend to support it in my projects for another year).

Yeah.. It's never easy to really find out when removing support for a specific version. Knowing that Node 6 and 8 are in LTS should eventually force everybody to upgrade. Using an unsupported version is definitely not ideal. But we'll continue to support Node 4 for some time until we really need to remove it (for performance/security reasons for example) and people still using it won't be able to upgrade to newer versions of this plugin then.

Anyway. Thanks for the PR!

You're welcome 😄