TypeScript Compile-Time Magic: Extracting Type Information for Runtime Business Rules

This article explores an innovative technical solution that transforms TypeScript static type information into runtime business logic. The author analyzes TypeScript’s abstract syntax tree (AST) and leverages the Compiler API to extract relationship descriptions and validation rules from type definitions, converting them into executable JSON configuration files. This approach allows developers to maintain only a single set of type definitions while automatically generating business model relationships and data validation rules, streamlining the development process. The article details the implementation principles, including using Phantom Types to embed metadata within types, and demonstrates through concrete code examples how to extract information from TypeScript types and apply it to runtime validation. This attempt opens up new application possibilities for TypeScript’s type system, showcasing an innovative approach to extending static analysis capabilities into runtime scenarios.