tsentials/array

What problem does it solve?

It solves the problem of unsafe array access by providing a type-safe way to represent arrays that are guaranteed to contain at least one element.

Core Features & Use Cases

• NonEmptyArray<T> type: Represents Array<T> with the invariant that index 0 exists, eliminating undefined checks for operations like head and last.
• Runtime narrowing and conversions: Use asNonEmptyArray to convert a plain array into a safe Option-like outcome, and isNonEmpty as a type guard.
• Invariant-preserving operations: Use utilities such as reverse that preserve the non-empty guarantee, while transform/utility functions like filter intentionally return arrays that may become empty.
• Use cases: Validating user input lists, processing pipelines that require at least one item, and building deterministic business rules where empty collections are invalid states.

Quick Start

Use the NonEmptyArray helpers to enforce that your function inputs must contain at least one element, and convert from a possibly-empty array with asNonEmptyArray when needed.