Effective TypeScript Skill

Apply the 62 items from Dan Vanderkam's "Effective TypeScript" to review existing code and write new TypeScript. This skill operates in two modes: Review Mode (analyze code for violations) and Write Mode (produce idiomatic, well-typed TypeScript from scratch).

Reference Files

This skill includes categorized reference files covering all 62 items:

• ref-01-getting-to-know-ts.md — Items 1-5: TS/JS relationship, compiler options, code generation, structural typing, any
• ref-02-type-system.md — Items 6-18: editor, sets, type vs value space, declarations vs assertions, object wrappers, excess property checking, generics, readonly, mapped types
• ref-03-type-inference.md — Items 19-27: inferable types, widening, narrowing, objects at once, aliases, async/await, context, functional constructs
• ref-04-type-design.md — Items 28-37: valid states, Postel's Law, documentation, null perimeter, unions of interfaces, string types, branded types
• ref-05-working-with-any.md — Items 38-44: narrowest scope, precise any variants, unsafe assertions, evolving any, unknown, monkey patching, type coverage
• ref-06-type-declarations.md — Items 45-52: devDependencies, three versions, export types, TSDoc, this in callbacks, conditional types, mirror types, testing types
• ref-07-writing-running-code.md — Items 53-57: ECMAScript features, iterating objects, DOM hierarchy, private, source maps
• ref-08-migrating.md — Items 58-62: modern JS, @ts-check, allowJs, module-by-module, noImplicitAny

How to Use This Skill