error-handling

To handle errors as values in TypeScript, return an Error instance on failure or an { ok: true, data } object on success. This pattern uses discriminated unions to separate success from failure, ensuring predictable behavior across application layers.

The best way to propagate type-safe errors across a Node.js service layer is using custom error classes with explicit context and status codes. Returning these instances as values ensures consistent error propagation and enables robust recovery patterns at API boundaries.

TypeScript error handling with exceptions obscures logic paths because thrown errors bypass the normal control flow, making it difficult to track error propagation. Returning errors as values with an ok: true discriminator clearly separates success from failure for stronger type-safety.

Yes, you can use discriminated unions for error handling in your data access layer. By returning objects with an ok: true discriminator for success and custom error instances for failures, you achieve type narrowing and predictable behavior across data access boundaries.

Yes, you need custom error classes to return errors as values in TypeScript. Defining these classes with explicit contextual data and status codes allows you to apply robust recovery patterns and ensures consistent, type-safe error propagation across layers.

You should not use throw for error handling in Node.js applications when you need predictable behavior across service and API boundaries. Returning errors as values using discriminated unions prevents obscured error paths and ensures stronger type-safety.