# Flatten Depth Array

Flatten array to specified depth using lodash _.flattenDepth

> Canonical page: https://elysiatools.com/en/tools/flatten-depth-array

- **Category:** Data Processing

- **Keywords:** array, flatten, depth, nested, lodash, level

## Overview

Flatten an array up to a specified depth level (nesting flattened to the specified level).

## Features:
- Accepts deeply nested JSON arrays of any depth
- Customizable flatten depth (1-10 levels)
- Precise control over flattening level
- Handles arrays with mixed data types
- Uses lodash _.flattenDepth for controlled flattening

## Examples:
- Depth 1: [1, [2, [3, [4]]], 5] → [1, 2, [3, [4]], 5]
- Depth 2: [1, [2, [3, [4]]], 5] → [1, 2, 3, [4], 5]
- Depth 3: [1, [2, [3, [4]]], 5] → [1, 2, 3, 4, 5]

## Use Cases:
- **Controlled Transformation**: Flatten to a specific level while preserving deeper structure
- **Data Processing**: Process nested arrays level by level
- **Partial Flattening**: Reduce nesting without losing all structure
- **Progressive Operations**: Apply transformations at specific nesting levels

## Inputs

- **Array Input** (textarea): Enter a valid JSON array with deeply nested elements
- **Flatten Depth** (number): Number of levels to flatten (1-10)

## When to use

- When you need to flatten an array to a specific depth while keeping deeper nested elements intact.
- For processing nested arrays level by level in data transformation or analysis workflows.
- To partially flatten arrays without losing all hierarchical structure.

## How it works

- Enter a valid JSON array with nested elements in the input field.
- Set the desired flatten depth between 1 and 10 (defaults to 2 if not specified).
- The tool applies lodash _.flattenDepth to flatten the array to the given depth.
- Receive the flattened array as text output.

## Use cases

- Flattening nested API response data for easier parsing and display.
- Preparing hierarchical data structures for database storage or further processing.
- Simplifying complex arrays in JavaScript applications for rendering or calculations.

## Frequently asked questions

### What is the maximum depth allowed?

You can set the depth from 1 to 10 levels.

### What input format is required?

The input must be a valid JSON array with any level of nesting.

### Can it handle arrays with mixed data types?

Yes, it processes arrays containing numbers, strings, and nested arrays.

### Is the depth parameter mandatory?

No, depth is optional and defaults to 2 if not provided.

### What if I provide invalid JSON?

The tool will return an error; ensure your input is a properly formatted JSON array.

## Related tools

- [Chunk Array](https://elysiatools.com/en/tools/chunk-array): Split array into chunks of specified size using lodash _.chunk
- [Fill Array](https://elysiatools.com/en/tools/fill-array): Fill array with value from start to end index using lodash _.fill
- [Flatten Array](https://elysiatools.com/en/tools/flatten-array): Flatten array one level deep using lodash _.flatten
- [From Pairs](https://elysiatools.com/en/tools/from-pairs): Convert array of key-value pairs to object using lodash _.fromPairs
- [Without Values](https://elysiatools.com/en/tools/without-values): Remove specified values from an array using lodash _.without
- [Assign Object](https://elysiatools.com/en/tools/assign-object): Assign source properties to a target object using lodash _.assign
- [Compact Array](https://elysiatools.com/en/tools/compact-array): Remove falsey values from array using lodash _.compact
- [Defaults Object](https://elysiatools.com/en/tools/defaults-object): Apply default values to an object using lodash _.defaults

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