typescript-expert

TypeScript language expertise covering the type system, generics, utility types, advanced type patterns, and project configuration. Use this skill whenever writing, reviewing, or refactoring TypeScript code, designing type-safe APIs, working with complex generics, debugging type errors, configuring tsconfig.json, migrating JavaScript to TypeScript, or leveraging TypeScript 5.x features like satisfies, const type parameters, decorators, and the using keyword. Also use when the user asks about type narrowing, conditional types, mapped types, template literal types, branded types, discriminated unions, or any TypeScript type system question — even seemingly simple ones, because TypeScript's type system has subtle gotchas that catch experienced developers.