Creating Custom Errors

Med

Extend Error class for semantic error handling. Add custom properties, proper stack traces, and type checking.

Interactive Visualization

Try/Catch/Finally Flow

try
error
catch
finally
Code executes normally

Key Points

  • Extend Error class
  • Set name property
  • Capture stack trace
  • Custom properties
  • instanceof checks

Code Examples

Custom Error Class

class ValidationError extends Error {
  constructor(message, field) {
    super(message);
    this.name = "ValidationError";
    this.field = field;
  }
}

throw new ValidationError("Required", "email");

Create semantic error types with custom properties