API parameter handling

Ensure consistent and safe handling of parameters and data across API endpoints. This includes using proper serialization methods, consistent parameter passing approaches, and context-aware processing when the same input may have different meanings.

Key practices:

• Use proper JSON serialization instead of string concatenation for API responses to prevent injection issues with user-provided data containing quotes or backslashes
• Maintain consistent behavior patterns across related endpoints (e.g., if login stores origin URL in cookies, signup should follow the same pattern)
• Pass parameters through appropriate channels - use hidden form fields instead of query parameters when dealing with sensitive or complex data
• Design APIs to handle context-specific interpretations where the same parameter might reference different entities based on the calling context

Example of proper JSON serialization:

// Instead of string concatenation:
return JSON.stringify(this.name) + ":" + JSON.stringify(data);

// Use proper object serialization:
const object = { name: this.name, light: {...}, dark: {...} };
return JSON.stringify(object, null, 2);

This approach prevents security vulnerabilities, ensures predictable API behavior, and provides better developer experience through consistent interfaces.