flattenDepth (Lodash Compatibility)

Use flatten from es-toolkit

This flattenDepth function operates slowly due to handling null or undefined. The flatten function from es-toolkit operates faster and simpler without this additional processing.

Use the faster and more modern flatten from es-toolkit instead.

Flattens an array to the specified depth.

const flattened = flattenDepth(array, depth);

Reference

flattenDepth(array, depth)

Use flattenDepth when you want to flatten a nested array to a desired depth. When you specify a depth, it flattens the nested array only to that depth.

import { flattenDepth } from 'es-toolkit/compat';

// Flatten to depth 1
flattenDepth([1, [2, [3, [4]], 5]], 1);
// Returns: [1, 2, [3, [4]], 5]

// Flatten to depth 2
flattenDepth([1, [2, [3, [4]], 5]], 2);
// Returns: [1, 2, 3, [4], 5]

// If no depth is specified, it defaults to 1
flattenDepth([1, [2, [3, [4]], 5]]);
// Returns: [1, 2, [3, [4]], 5]

null or undefined are treated as empty arrays.

import { flattenDepth } from 'es-toolkit/compat';

flattenDepth(null, 2); // []
flattenDepth(undefined, 2); // []

Parameters

• array (ArrayLike<T> | null | undefined): The array to flatten.
• depth (number, optional): The maximum depth to flatten. Default is 1.

Returns

(T[]): Returns a new array flattened to the specified depth.