eslint-plugin-no-dupe-class-fields

This project is an ESLint plugin which detects when classes have duplicate fields, including methods and properties.

class Foo {
  bar = 5;
  bar() {
    console.log('hello');
  }
}

let foo = new Foo();
foo.bar(); // Error because bar is 5. Whoops

This plugin will detect if there are multiple methods or properties with the same name on a single class. This plugin is an upgraded version of the built-in no-dupe-class-members rule, which does not detect class properties. When you use this plugin's recommended config, the built-in no-dupe-class-members rule will be disabled.

Class properties are currently an ECMAScript proposal, and are only supported with a babel plugin. ESLint does not support class properties by default, so you must currently use the babel-eslint parser with ESLint for this plugin to detect class properties.

Configuration

1. Install babel-eslint and this plugin: npm install --save-dev babel-eslint eslint-plugin-no-dupe-class-fields or yarn add --dev babel-eslint eslint-plugin-no-dupe-class-fields.
2. Set the ESLint config's parser property to babel-eslint.
3. Add plugin:no-dupe-class-fields/recommended to the ESLint config's extends list.

Example:

{
  "root": true,
  "parser": "babel-eslint",
  "env": {
    "node": true,
    "es6": true
  },
  "extends": ["eslint:recommended", "plugin:no-dupe-class-fields/recommended"],
  "plugins": [],
  "rules": {
    "indent": ["error", 2]
  }
}