React Debugging Guide

A systematic approach to debugging React applications, covering common error patterns, modern debugging tools, and step-by-step resolution strategies.

Common Error Patterns

1. "Cannot read property of undefined" / "TypeError: X is undefined"

Cause: Accessing properties on null/undefined values, often from:

• Uninitialized state
• API data not yet loaded
• Incorrect prop drilling

Solutions:

// Problem: Accessing nested property before data loads
const name = user.profile.name; // Error if user is undefined