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Version: Canary 🚧

no-window-eq-undefined

Disallow typeof window !== "undefined" checks as an SSR escape hatch.

Rule details​

In Docusaurus, using typeof window !== 'undefined' is not the recommended way to detect a browser environment. This check may not work correctly with Docusaurus's SSR/pre-rendering pipeline.

❌ Incorrect​

if (typeof window !== 'undefined') {
  // browser-only code
}

✅ Correct​

Use the useIsBrowser() hook from @docusaurus/useIsBrowser inside React components:

import useIsBrowser from '@docusaurus/useIsBrowser';

function MyComponent() {
  const isBrowser = useIsBrowser();
  if (isBrowser) {
    // browser-only code
  }
}

Or use ExecutionEnvironment.canUseDOM from @docusaurus/ExecutionEnvironment outside React:

import ExecutionEnvironment from '@docusaurus/ExecutionEnvironment';

if (ExecutionEnvironment.canUseDOM) {
  // browser-only code
}

Options​

This rule has no options.