Angular Debugging Guide

This guide provides a systematic approach to debugging Angular applications, covering common error patterns, debugging tools, and structured resolution phases.

Common Error Patterns

NullInjectorError

Symptoms:

• NullInjectorError: No provider for <ServiceName>
• StaticInjectorError: No provider for <ServiceName>
• Service injection fails at runtime

Root Causes:

1. Service not provided in any module or component
2. Circular dependency between services
3. Missing @Injectable() decorator
4. Service provided in wrong scope (lazy-loaded module vs root)