Remove dependency on the js/ package (and goja) from lib/* packages

[na--]

This doesn't depend on anything else, it should be safe to merge as is.

This should close #2535, I think 🤔 Between it and #2536, go.k6.io/lib and its sub-packages shouldn't depend on go.k6.io/js or github.com/dop251/goja, right?

go list -f '{{ join .Imports "\n" }}' ./... | sort -u | grep -E 'goja|go.k6.io/k6/js' returns no results in the lib/ package, at least 🤞

Unfortunately, I couldn't make depbuard work correctly, and I have no time to debug that further, so I'll leave that to someone else if they want to. From what I understand by skimming https://golangci-lint.run/usage/linters/#depguard, adding something like this in the linters-settings: section of .golangci.yml should have worked, but it didn't:

  depguard:
    list-type: denylist
    packages:
      - github.com/dop251/goja
      - go.k6.io/k6/js
      - go.k6.io/k6/js/**
    ignore-file-rules:
      - "js/**/*.go"
      - "cmd/*.go"

The goal is to ensure we don't import goja or the js package anywhere except js/ and cmd/, and maybe we can even restrict that further 🤔 If someone can make the linter work, that is 😅

[mstoykov]

nit: Do we need this to be a function 🤔

I guess for future proofing in case we start chaning what lib.State is returned. But IIRC we basically return the same struct eitherway.

We do need it to be a function on the VU as it is an interface. But I wonder if we can skip the inderection here 🤔

[na--]

I'd slightly prefer to keep the function, just so we keep the same sort of API structure and in case it might matter in the future, but I can make the change if others feel the same as you.

FWIW, I even considered adding another interface with just a State() *lib.State function in grpext/ and continuing to pass the VU directly, or even moving the whole DefaultOptions function back in the js/ package. The current approach seemed like a nice middle ground 😅

[oleiade]

👍🏻