Software⏱️ 2 min read📅 2026-05-31

How to Fix: jest spyOn not working on index file, cannot redefine property

Learn how to fix: jest spyOn not working on index file, cannot redefine property.

Quick Answer: Try checking your system settings or restarting.

📋 Table of Contents

  1. ✅ Solution
  2. ✨ Wrapping Up

The issue is caused by the way Jest handles imports in index.tsx. When you import UserContext directly, it creates a new scope for the import, which allows you to spy on it without any issues.

✅ Solution

Use a named import instead of default import

  1. Step 1: Import UserContext using the name instead of default import in both user-context.tsx and index.tsx.

Alternatively, you can use a __mocks__/user-context.ts file to mock the UserContext component. This way, you can spy on it without affecting the original import.

✨ Wrapping Up

By following these steps, you should be able to fix the issue and successfully spy on your UserContext component.

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