avoid-numeric-index

What problem does it solve?

JavaScript's runtime keys are always strings, while TypeScript supports number-index signatures as a compile-time fiction. This Skill guides developers to avoid { [n: number]: T } and choose Array<T>, tuple, ArrayLike<T>, or Map<number, T> when modeling collections.

Core Features & Use Cases

• Understand the runtime behavior of object keys and why numeric indices are not real indices at runtime.
• Learn when to prefer arrays, tuples, ArrayLike<T>, or Map<number, T> over numeric index signatures in type definitions.
• Apply guidance to common scenarios like modeling sequences, fixed-length data, and keyed collections that rely on numeric keys.

Quick Start

Replace any numeric index signature with an Array or Map in your TypeScript types and verify runtime key behavior.