domain-primitives-and-always-valid

An always-valid domain model enforces invariants at construction time using domain primitives, ensuring objects can never exist in an invalid state. By wrapping raw primitive types in immutable, domain-specific types, it prevents invalid states and improves code readability.

To implement a smart constructor, define a factory method that validates range constraints and non-empty sequences before instantiating an immutable domain primitive. This ensures only valid values are created, preventing invalid instances throughout the domain layer.

Yes, domain primitives provide language-agnostic guidance to model composite values like Money, Age, and Email. They apply to Rust, TypeScript, Java, and other languages to wrap primitive values and enforce invariants at construction.

The best way to refactor raw primitive types is to wrap them in domain-specific, immutable types using smart constructors. This approach removes dependence on raw primitives, enforces invariants at construction, and enables stronger compiler-time guarantees.

You should use domain primitives instead of raw primitive types to enforce invariants at construction and ensure safety. Wrapping primitives in immutable, domain-specific types removes dependence on raw values, improves code readability, and enables stronger compiler-time guarantees.

Yes, designing domain-specific, immutable types supports both new feature work and existing code refactoring. It applies to Rust, TypeScript, Java, and other languages to model values safely and support reviews throughout the domain layer.