What is the Single-or-Array pattern?

It is a design pattern where a function is defined to accept either a single object or an array of those objects, normalizing the input into an array internally for unified processing.

When should I avoid using the Single-or-Array pattern?

Skip this pattern if the single and batch versions of your function have significantly different side effects, different return types, or require distinct configuration options.

How does this pattern reduce code duplication?

Instead of writing separate 'createOne' and 'createMany' functions, you use a single public API that delegates all real logic to one internal array-only implementation.

Why use function overloads with this pattern?

Overloads provide better IDE autocompletion and type safety, ensuring the return type accurately reflects whether the user passed a single item or an array.

Single-or-Array Pattern

Name: Single-or-Array Pattern
Author: EpicenterHQ

byEpicenterHQ

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3,817

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API Development

Normalizes functions to accept both single items and arrays for flexible, type-safe API design and batch processing.

This skill provides a standardized implementation pattern for TypeScript/JavaScript functions that need to handle either a single input or a collection of inputs seamlessly. By using function overloads and internal normalization, it allows developers to create intuitive APIs for CRUD operations and batch processing that eliminate logic duplication. It ensures that functions remain easy to use for single items while remaining powerful enough for bulk operations, providing a cleaner developer experience and more maintainable codebases.

Key Features

01Standardized naming conventions for parameters and variables

02Pre-defined patterns for CRUD, batch APIs, and factory functions

03Input normalization logic using Array.isArray() checks

043,817 GitHub stars

05Centralized internal implementation to prevent logic duplication

06TypeScript function overload patterns for enhanced IDE intelligence

Use Cases

01Creating batch processing APIs that don't force single items into arrays

02Designing flexible CRUD operations that handle single or multiple records

03Building service factories that accept variable dependency configurations

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add epicenterhq/epicenter single-or-array-pattern

For use in Claude.ai and ChatGPT

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