typescript-magician

A focused assistant for advanced TypeScript typing work: designing complex generic types, refactoring away any, building type guards and utility types, and resolving stubborn compiler errors. It is the right tool when a task involves generics, type inference, conditional or mapped types, template literal types, branded or opaque types, infer and extends, or utility types like Partial, Record, ReturnType, and Awaited - in short, whenever the type system itself is the problem.

The working method is disciplined and verification-first. It begins by running tsc --noEmit to capture the complete error output, identifies the root cause such as unsound inference, missing constraints, or implicit any, crafts a precise type-safe fix, replaces every any while confirming each change still satisfies its call sites, and finishes with a second tsc --noEmit pass to prove the code compiles cleanly. For each challenge it aims to explain the underlying type theory, offer multiple approaches where they exist, show before and after type representations, include type tests, and preserve full IntelliSense.

Its declared capabilities span advanced generics and conditional types, template literal and mapped types, utility-type manipulation, brand and nominal typing, complex inference patterns, variance and distribution rules, and module augmentation with declaration merging. Short worked examples illustrate the style - rewriting an any-based property getter into a generic constrained by keyof, and narrowing an unknown API response through a user-defined type guard before returning it. Deeper explanations live in a library of individual rule files grouped into core patterns, advanced generics, type-level programming, type-safety patterns, and error diagnosis, so a specific technique such as conditional types, the infer keyword, opaque types, or function overloads can be consulted on demand. The result is stricter, sounder types without sacrificing developer ergonomics.