eslint-rule-starter

Template for writing eslint rules

Getting started

Yarn

yarn && yarn run lint

NPM

npm install && npm run lint

Writing a rule

ESLint first parses code into an abstract syntax tree (AST) before checking any rules. So to write a rule you must understand the AST representation of your code.

Use https://astexplorer.net/ to view AST of your code and also write new rules.

Configuring https://astexplorer.net/

1. set parser (</>) to '@babel/eslint-parser'
2. set Transform option to 'ESLint v4'
3. paste sample code in the top-left pane
4. write eslint rule in bottom-left pane

Scaffolding/Project Setup

• eslint rules must be in a separate package with their own package.json file In this example I have added the package with yarn add --dev file:./packages/eslint-plugin-sample
• the package name must start with eslint-plugin-
• add the package to package.json dependencies
• add the package as a plugin in .eslintrc.js without the eslint-plugin- prefix