fixed-len-array

📐 fixed-len-array

A tiny and type-safe TypeScript utility to create and work with fixed-length arrays (tuples). Automatically trims or pads input arrays at runtime, while offering compile-time safety using TypeScript's type system.

✨ Features

• ✅ Enforces fixed-length array types (tuples)
• 🧠 Type-safe construction
• 🔧 Automatically trims or pads at runtime
• 🔄 Pads with a custom value or falls back to null if not provided
• 📦 Tiny, no dependencies
• 🔁 Works in both Node.js and browser environments (ESM only)

🚀 Usage

npm install fixed-len-array

import { toFixedLengthArray, FixedLengthArray } from "fixed-len-array";

// Pads to a fixed length of 3 with custom default
const vec3 = toFixedLengthArray([1], 3, 0);
// Result: [1, 0, 0]

// If no default is provided, pads with `null`
const paddedWithNull = toFixedLengthArray([1], 3);
// Result: [1, null, null]

// Trims if input is longer
const trimmed = toFixedLengthArray([1, 2, 3, 4, 5], 3, 0);
// Result: [1, 2, 3]

// Full type support
type Vec3 = FixedLengthArray<3, number>;

🧪 API

toFixedLengthArray<T, N>(input: T[], fixedLength: N, defaultValue?: T): FixedLengthArray<N, T>

Creates a fixed-length array by trimming or padding the input. If defaultValue is omitted, null will be used for padding.

type FixedLengthArray<N, T>

A recursive type that represents a tuple of length N, with all elements of type T.

🤝 Contributing

We welcome contributions! Please see our Contributing Guide for details.

Development Setup

# Clone repository
git clone https://github.com/ptprashanttripathi/fixed-len-array.git
cd fixed-len-array

# Install dependencies
npm install

# Build TypeScript
npm run build

# Run tests
npm test

📄 License

This project is MIT licensed.

Made with ❤️ by Pt. Prashant Tripathi

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