What is the best way to add eslint-plugin-qunit?

[tylervz]

I got MegaLinter to use eslint-plugin-qunit which has rules for linting QUnit tests, but I'm not sure the way I went about it is recommend or considered best practice. Can someone let me know what the best way to do so is?
I know there are specific ESLint plugins already installed on the mega-linter Docker image:

https://github.com/oxsecurity/megalinter/blob/main/docs/descriptors/javascript_eslint.md#installation-on-mega-linter-docker-image

Describe the solution you'd like
I would like to have MegaLinter use eslint-plugin-qunit which has rules for linting QUnit tests, or add a configurtion variable JAVASCRIPT_ES_ADDITIONAL_PLUGINS so users can specify additional ESLint plugins to be installed before ESLint runs i.e. ["eslint-plugin-qunit@latest", "eslint-plugin-jquery"], or update the documentation with a GitHub Actions example of how to install additional ESLint plugins (I could take on this task, if in fact my method of installing additional ESLint plugins is recommended).

Describe alternatives you've considered

The relevant part of my .eslintrc.yml file (which is in the root of my repository) is:

###########
# Plugins #
###########
plugins:
  - "@typescript-eslint"

#########
# Rules #
#########
extends: ["eslint:recommended", "plugin:qunit/recommended"]
rules:
  array-callback-return: "error"

I was able to use eslint-plugin-qunit by adding it as a dev dependency in my package.json and running npm install before the MegaLinter action.

jobs:
  build:
    name: MegaLinter
    runs-on: ubuntu-latest
    steps:
      # Git Checkout
      - name: Checkout Code
        uses: actions/checkout@v3
        with:
          token: ${{ secrets.PAT || secrets.GITHUB_TOKEN }}
          fetch-depth: 0

      - name: Setup node
        uses: actions/setup-node@v3
        with:
          node-version: 16
          cache: npm
      # Install the npm dependencies
      - name: Install packages for Node
        run: npm install

      # MegaLinter
      - name: MegaLinter
        id: ml
        # You can override MegaLinter flavor used to have faster performances
        # More info at https://oxsecurity.github.io/megalinter/flavors/
        uses: oxsecurity/megalinter@v6
        env:
          # All available variables are described in documentation
          # https://oxsecurity.github.io/megalinter/configuration/
          VALIDATE_ALL_CODEBASE: false
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

This was after I had first tried adding the following to .mega-linter.yml:

JAVASCRIPT_ES_PRE_COMMANDS:
  - command: "npm install eslint-plugin-qunit@latest --save-dev"
    cwd: "workspace" # Will be run at the root of the workspace (usually your repository root)
  - command: "npm list --depth=0"
    cwd: "workspace"

And then the run failed because the npm install command ran in /node-deps rather than /github/workspace:

- Using [eslint v8.33.0] https://megalinter.io/6.19.0/descriptors/javascript_eslint
  - MegaLinter key: [JAVASCRIPT_ES]
  - Rules config: identified by [eslint]
  - Number of files analyzed: [7]
  [Pre][JAVASCRIPT_ES] run: [cd /node-deps && npm install eslint-plugin-qunit@latest --save-dev] in cwd [/github/workspace]
  [Pre][JAVASCRIPT_ES] 
  added 3 packages, removed 2 packages, changed 2 packages, and audited 2324 packages in 10s
  
  227 packages are looking for funding
    run `npm fund` for details
  
  15 vulnerabilities (2 moderate, 12 high, 1 critical)
  
  To address issues that do not require attention, run:
    npm audit fix
  
  To address all issues (including breaking changes), run:
    npm audit fix --force
  
  Run `npm audit` for details.
  
  [Pre][JAVASCRIPT_ES] run: [npm list --depth=0] in cwd [/github/workspace]
  [Pre][JAVASCRIPT_ES] [email protected] /github/workspace
  └── (empty)
  
  
  --Error detail:
  
  Oops! Something went wrong! :(
  
  ESLint: 8.33.0
  
  ESLint couldn't find the plugin "eslint-plugin-qunit".
  
  (The package "eslint-plugin-qunit" was not found when loaded as a Node module from the directory "/github/workspace".)

[nvuillam]

The pre-command is today the only way to add additional npm packages
But your proposition of JAVASCRIPT_ES_ADDITIONAL_PLUGINS looks very interesting, we'll see what we can do :)