francoismassart/eslint-plugin-demo-typescript

Demonstrating an ESLint plugin using TypeScript

Writing a custom ESLint plugin with TypeScript code

This repo is based on the "Writing a custom ESLint plugin with Typescript" Medium article written by Adam Thompson .

Why this repo?

I was expecting to find a link to a repo with the full code explained in Adam's article but I could not find it.

It will be a quick way to browse the full code on its own and possibly to enhance it by fixing issues.

Getting started

I worked on this repo using pnpm but it should work with other package manager.

Install

pnpm i

Build

pnpm build

Test

Tests were setup to work with jest and vitest both comes with pros and cons...

I would recommend Vitest but I also added Jest in case you want it.

Jest	Vitest
Based on commonjs	Based on ESM
✅ Mocking	✅ Mocking
✅ Snapshots	✅ Snapshots
✅ Parallel testing	✅ Parallel testing
✅ Fast	✅ Often faster
-	✅ Support benches
❌ Require ts-jest lib	❌ Requires setupFile and vitest.config.ts

NB: In order to use, the RuleTester from @typescript-eslint/rule-tester, we must:

• Have a tsconfig.json with:

  {
    "compilerOptions": {
      "module": "nodenext",
      "moduleResolution": "nodenext"
    }
  }
  

  More info can be found on v6: Cannot find module @typescript-eslint/* or its corresponding type declarations.

  You can use bundler, node16, or nodenext for moduleResolution.

• Use eslint with v8, typescript-eslint does not support v9 yet

Using vitest

pnpm test

Using jest

pnpm test:jest

Docs

pnpm docs:init will create new files for each rule if necessary.

pnpm docs:update will update existing files and the rules list.

You can see an example of generated documentation in the nex section.

Rules

💡 Manually fixable by editor suggestions.

Name	Description	💡
my-rule	An example ESLint rule	💡