flattenDepth

INFO

This function is only available in es-toolkit/compat for compatibility reasons. It either has alternative native JavaScript APIs or isn’t fully optimized yet.

When imported from es-toolkit/compat, it behaves exactly like lodash and provides the same functionalities, as detailed here.

Flattens an array up to the specified depth.

Signature

function flattenDepth<T, D extends number = 1>(value: T[], depth: D): Array<FlatArray<T[], D>> | [];

Parameters

• value (T[]): The value to flatten.

value can be ArrayLike<T>, null, or undefined

To ensure full compatibility with lodash, the flattenDepth function handles value in this way:

• If value is an ArrayLike<T>, it gets converted into an array using Array.from(...).
• If value is null or undefined, it will be treated as an empty array.

• depth (D): The depth level specifying how deep a nested array structure should be flattened. Defaults to 1.

Returns

(Array<FlatArray<T[], D>> | []): A new array that has been flattened.

Examples

const arr = flattenDepth([1, [2, 3], [4, [5, 6]]], 1);
// Returns: [1, 2, 3, 4, [5, 6]]

const arr = flattenDepth([1, [2, 3], [4, [5, 6]]], 2);
// Returns: [1, 2, 3, 4, 5, 6]