Implement domain-driven design business logic with contract-based state transitions in TypeScript.
npx skills add https://github.com/fyuuki0jp/seizu --skill seizu
Please help me install this Agent Skill. Skill: seizu Source: https://github.com/fyuuki0jp/seizu/tree/main/.claude/skills/seizu Command: npx skills add https://github.com/fyuuki0jp/seizu --skill seizu
This Skill helps developers build trustworthy code by implementing business logic as declarative contracts, enabling automated verification and reducing review overhead.
Use the seizu skill to define a new cart contract for adding items.
High-intent search queries and answers about installing and using this skill.
You can implement domain-driven design business logic in TypeScript by defining declarative contracts for state transitions. This approach enforces immutability and uses Railway Oriented Programming to handle domain errors functionally.
Contract-based state transitions work by declaratively defining aggregate states, domain errors, and command handlers in TypeScript. Business rules are enforced strictly through these contracts, ensuring valid state changes within the domain layer.
You can verify domain logic invariants and business rules automatically using Property-Based Testing. This method tests postconditions against defined contracts to ensure state transitions and use case scenarios function correctly.
The best way to enforce immutability and functional programming in a domain layer is by using contract-based state transitions with Railway Oriented Programming. This ensures state changes are predictable and domain errors are handled functionally.
Yes, you can build an e-commerce shopping cart by implementing command handlers as contracts. This ensures business rules like item duplication and stock availability are strictly enforced and automatically tested.
A limitation of contract-based domain logic is that it requires strict adherence to immutability and functional programming principles. It may not suit applications where domain rules are highly dynamic or frequently change at runtime.
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