Finally made my node production server stable enough that I could focus on writing tests*. I start by setting up docker, mocking cognito, preparing the database and everything. Reading up on Node test suites and following a short tut to set up my first unit test. Didn't go smoothly, but it's local and there are no deadlines so who cares. 4 days later, first assert.equal(1+1, 2) passes and I'm happy.

I start writing all sorts of tests, installing everything required into "devDependancies," and getting the joy of having some tests pass on first try with all asserts set up, feels good!

I decide to make a small update to production, so I add a test, run and see it fail, implement the feature, re-run and, it passes!

I push the feature to develop, test it, and it works as intended. Merge that to master and subsequently to one of my ec2 production servers**, and lo and behold, production server is on a bootloop claiming it "Cannot find module `graphql`". But how? I didn't change any production dependencies, and my package lock json is committed so wth?

I google the issue, but can't find anything relevant. The only thing that I could guess was that some dependencies (including graphql) were referenced*** in both, prod and dev, and were omitted when installed on a prod NODE_ENV, but googling that specific issue yielded no results, and I would have thought npm would be clever enough to see that and would always install those dependencies (spoiler: it didn't for me).

With reduced production capacity (having one server down) I decided to npm uninstall all dev dependencies anyway and see what happens. Aaaaand it works.....

So now I have a working production server, but broken local tests, and I'm not sure why npm is behaving like this...

* Yes I see the irony.
** No staging because $$$, also this is a personal project.
*** I am not directly referencing the same thing twice, it's probably a subdependency somewhere.