Dropping support for node 4

[rickerbh]

Are you guys open to the idea of dropping support for node4? I ask because of a couple of reasons.

1. On 30 April 2018 node 4 hit end of life, and node.js themselves no longer support it. https://github.com/nodejs/Release
2. Firestore requires node>=6.0.0, and the firestore plugin I've developed won't work with node4.

Thoughts?

[adrai]

dropping support, yes.
but this should not mean, it should not run with node 4...
just my opinion

[nanov]

Just an idea, couldn't we check node version if plugin is initialized ( process.version ), and then output an appropriate warning/error message just for this plugin?

[adrai]

can do this also for all plugins and check the engines value in the appropriate package.json

=> https://github.com/googleapis/nodejs-firestore/blob/master/package.json#L8

[nanov]

much better!

[adrai]

@rickerbh ?

[adrai]

I just created a branch: https://github.com/adrai/node-viewmodel/compare/warn-version-mismatch