[SOLVED] Local npm dependency in Ember.js 5.8

Local npm dependency in Ember.js 5.8

I need custom linting rules for my Ember 5.8 project. Ember 5.8 uses ESLint 8.57 and ESLint allows custom rules via Plugin, see this tutorial. Step 8 of said tutorial reads as follows:

You might want to use a locally defined plugin in one of the following scenarios:

You want to use a plugin, but do not want to publish it to npm.

That's what I want: local, not published. But in order to make it work I had to introduce the ESLint Plugin as a local dependency to npm, which isn't mentioned in the tutorial, but described here (based on here):

{
  // ...
  "devDependencies": {
    // ...
    "eslint-plugin-acme": "file:./config/eslint"
  }
}

That "works" in terms of "npm install picks it up" and "npm run lint works as expected".

But: It does not work for Ember: npx ember build throws

Missing npm packages: 
Package: eslint-plugin-acme
  * Specified: file:./config/eslint
  * Installed: (not installed)

Run `npm install` to install missing dependencies.

Stack Trace and Error Report: /tmp/error.dump.8b24e5db90b94e60ef96136863733d8a.log
An error occurred in the constructor for ember-cli-dependency-checker at /home/crusy/code/acme/frontend/node_modules/ember-cli-dependency-checker

What's the problem? Again, npm install works, why is ember-cli-dependency-checker recommending it?

Solution

Ok, while npm install seemed to be happy, I had to add a package.json to ./config/eslint:

{
    "name": "eslint-plugin-acme",
    "version": "1.0.0",
    "author": "crusy"
}

And link it: npm link ./config/eslint/ --save. Now npx ember build works as well.