How do I fix this instantly in my terminal?

On macOS & Linux run: "// Add at top of file: 'use client';". On Windows PowerShell run: "// Add at top of file: 'use client';". This terminates the conflicting process or resets the state without rebooting your computer.

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No. All commands, code snippets, and developer utilities on DevTransform run 100% locally in your browser or terminal. No telemetry, no logs, and zero tracking.

JavaScript & Node Error

Fix "ReferenceError: window is not defined" in Next.js & React SSR

Developer guide and instant terminal command to diagnose and solve this error.

Terminal Output

$ReferenceError: window is not defined (or document is not defined)

Why Does This Error Happen?

Code accessing browser-only APIs (window, document, localStorage, navigator) was executed on the server during Server-Side Rendering (SSR) or Static Site Generation (SSG).

Instant Terminal One-Liner Fixes

Choose your operating system

Linux (Bash / Zsh)

// Add at top of file: 'use client';

macOS (Terminal / iTerm2)

// Add at top of file: 'use client';

Windows (PowerShell Run as Administrator)

// Add at top of file: 'use client';

Comprehensive Step-by-Step Resolution

1Guard window access with "typeof window !== 'undefined'".
2Move browser-dependent initialization inside a "useEffect(() => { ... }, [])" hook.
3In Next.js App Router, add "'use client';" at the very top of the file.
4Use dynamic import with ssr: false: "const DynamicComp = dynamic(() => import(...), { ssr: false })".

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Troubleshoot using the TypeScript Interface Generator

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Frequently Asked Questions

Everything you need to know regarding specifications, syntax, and security best practices.

Code accessing browser-only APIs (window, document, localStorage, navigator) was executed on the server during Server-Side Rendering (SSR) or Static Site Generation (SSG).

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