node-array-flatten

A modern, efficient, and lightweight utility for flattening nested arrays in Node.js and JavaScript environments. This package leverages the native Array.prototype.flat() method for optimal performance and simplicity, providing a robust solution for transforming multi-dimensional arrays into single-dimensional ones.

Features

• Optimal Performance: Utilizes the highly optimized native Array.prototype.flat() for fast array flattening.
• Depth Control: Supports flattening to a specified depth or completely flattening all nested arrays.
• Simple API: Easy to use with a clear and intuitive function signature.
• Robust Input Validation: Ensures the input is always an array, throwing an error for invalid types.

Installation

npm install node-array-flatten

Usage Example

The flatten function takes an array as its first argument and an optional depth as its second argument.

Basic Usage (Deep Flatten)

By default, if no depth is specified, the function performs a deep flatten, concatenating all sub-array elements into a single-dimensional array, regardless of nesting level.

// For CommonJS (Node.js older versions or default Node.js modules)
const flatten = require('node-array-flatten');

// For ES Modules (modern Node.js with type: "module" in package.json)
// import flatten from 'node-array-flatten';

const nestedArray = [1, [2, 3], 4, [5, [6, 7], null, undefined, 0, false]];
const flattenedArray = flatten(nestedArray);

console.log('Deep Flatten Example:');
console.log(flattenedArray);
// Expected Output: [1, 2, 3, 4, 5, 6, 7, null, undefined, 0, false]

Flattening to a Specific Depth

You can control how many levels deep the array is flattened by providing a depth argument.

const deeplyNested = [1, [2, [3, 4]], 5, [6, [7, [8, 9]]]];

// Flatten one level deep
const oneLevelFlattened = flatten(deeplyNested, 1);
console.log('\nFlatten 1 Level Deep:');
console.log(oneLevelFlattened);
// Expected Output: [1, 2, [3, 4], 5, 6, [7, [8, 9]]]

// Flatten two levels deep
const twoLevelsFlattened = flatten(deeplyNested, 2);
console.log('\nFlatten 2 Levels Deep:');
console.log(twoLevelsFlattened);
// Expected Output: [1, 2, 3, 4, 5, 6, 7, [8, 9]]

// Explicitly flatten all levels (same as default if no depth is given)
const infinityFlattened = flatten(deeplyNested, Infinity);
console.log('\nFlatten All Levels (Infinity):');
console.log(infinityFlattened);
// Expected Output: [1, 2, 3, 4, 5, 6, 7, 8, 9]

Handling Invalid Input

The function strictly requires an array as input. Passing a non-array value will result in an error.

try {
    flatten('This is not an array!');
} catch (error) {
    console.error('\nError Example:');
    console.error(error.message);
}
// Expected Output: Error: Input must be an array!

try {
    flatten(123);
} catch (error) {
    console.error(error.message);
}
// Expected Output: Error: Input must be an array!

Here's the Markdown text for your API, Compatibility, Contributing, and License sections, formatted clearly for your README.md file:

---

API

flatten(arr, [depth])

• arr (Array, required): The array to be flattened.
• depth (number, optional, default: Infinity): The number of levels to flatten.
  • Set to 1 to flatten only the first level of nested arrays.
  • Set to Infinity (or omit) to flatten all nested arrays recursively into a single-dimensional array.

Returns: A new Array with the sub-array elements concatenated into it.

Throws: An Error if arr is not an array.

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Compatibility

This package relies on Array.prototype.flat(), which is natively available in Node.js versions >=12.0.0. If you need to support older Node.js environments, consider polyfilling Array.prototype.flat() or using a different flattening utility.

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Contributing

We welcome contributions to node-array-flatten! If you have suggestions for improvements, bug reports, or want to contribute code, please feel free to:

1. Open an issue: Describe the bug or feature request in detail.
2. Submit a pull request:
   • Fork the repository.
   • Create a new branch for your feature or bug fix.
   • Write clear, concise code that adheres to the project's style.
   • Add or update tests to cover your changes.
   • Ensure all tests pass.
   • Submit your pull request, referencing any relevant issues.

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License

This project is licensed under the MIT License.

See the LICENSE file for more details.