ESLint Plugin: no-typeof-window-undefined

0.0.2 verified Sat Apr 25 auth: no javascript

ESLint rule (version 0.0.2) that flags typeof window === 'undefined' patterns used for SSR checks. Encourages using a helper like `import { isBrowser } from 'some-ssr-helper'` for cleaner and more maintainable code. No updates since initial release. Minimal, single-rule plugin with peer dependency on ESLint ^4-^8.

Common errors

error ESLint couldn't find the plugin "eslint-plugin-no-typeof-window-undefined" ↓

cause Plugin not installed or not added to plugins array.

fix

npm install --save-dev eslint-plugin-no-typeof-window-undefined and add to plugins: ['no-typeof-window-undefined']

error Definition for rule 'no-typeof-window-undefined' was not found ↓

cause Rule name used without plugin prefix in rules config.

fix

Use 'no-typeof-window-undefined/no-typeof-window-undefined': 'error'

Warnings

gotcha Rule name is 'no-typeof-window-undefined/no-typeof-window-undefined' – you must prefix with the plugin namespace. ↓

fix Use 'no-typeof-window-undefined/no-typeof-window-undefined': 'error' in rules.

gotcha Does not support ESLint flat config (ESLint 9+). No updated version. ↓

fix Manually adapt plugin to flat config format or use legacy eslintrc.

Install

npm install eslint-plugin-no-typeof-window-undefined

yarn add eslint-plugin-no-typeof-window-undefined

pnpm add eslint-plugin-no-typeof-window-undefined

Imports

default

wrong

module.exports = {
  plugins: ['no-typeof-window-undefined'],
  rules: { 'no-typeof-window-undefined': 'error' }
};

correct

module.exports = {
  plugins: ['no-typeof-window-undefined'],
  rules: { 'no-typeof-window-undefined/no-typeof-window-undefined': 'error' }
};

Rule name is the full plugin name; you must prefix with the plugin name.

rules

wrong

const { rules } = require('eslint-plugin-no-typeof-window-undefined');

correct

const plugin = require('eslint-plugin-no-typeof-window-undefined');
// then use plugin.rules['no-typeof-window-undefined']

CommonJS; no default export, so destructure from module.exports.

flat config (ESLint 9+)

wrong

import plugin from 'eslint-plugin-no-typeof-window-undefined';
export default [
  { plugins: ['no-typeof-window-undefined'], ... }
];

correct

import noTypeofWindowUndefined from 'eslint-plugin-no-typeof-window-undefined';
export default [
  { plugins: { 'no-typeof-window-undefined': noTypeofWindowUndefined },
    rules: { 'no-typeof-window-undefined/no-typeof-window-undefined': 'error' } }
];

ESLint 9+ flat config requires an object with plugin key, not array.

Quickstart

Shows how to install and configure the ESLint plugin to flag typeof window === 'undefined' and suggests using a helper function instead.

// .eslintrc.js (ESLint <=8)
module.exports = {
  plugins: ['no-typeof-window-undefined'],
  rules: {
    'no-typeof-window-undefined/no-typeof-window-undefined': 'error'
  }
};

// Example of flagged code:
if (typeof window === 'undefined') { /* server code */ }

// Suggested fix:
import { isBrowser } from 'some-helper';
if (!isBrowser) { /* server code */ }