JavaScript flat()Method

JavaScript Array Object

Example

Recursively traverse the array to a specified depth:

let nestedArray = [1, 2, [3, 4, [5, 6]]]; let flatArray = nestedArray.flat(); console.log(flatArray); //Output: [1, 2, 3, 4, [5, 6]] //Specify depth as 2 let deeplyNestedArray = [1, 2, [3, 4, [5, 6]]]; let deeplyFlatArray = deeplyNestedArray.flat(2); console.log(deeplyFlatArray); //Output: [1, 2, 3, 4, 5, 6]

The output result is:

Try it Yourself »

In the above example, the flat() method is used to flatten the nested array nestedArray into a one-dimensional array. In the second example, by passing a depth parameter, the nested array deeplyNestedArray can be deeply flattened.

Note that the flat() method returns a new array, and the original array is not affected.

Definition and Usage

The flat() method recursively traverses the array at a specified depth and merges all elements and the elements of sub-arrays encountered into a new array, which is returned.

The flat() method returns a new array containing all elements of the array and sub-arrays.

The flat() method recursively traverses the array, extracts all nested array elements, and generates a new one-dimensional array.

Browser Support

The numbers in the table indicate the first browser version that supports the method.

Syntax

flat()
flat(depth)

Parameters

Technical Details

More Examples

Flatten nested arrays

Flattening and array holes:The flat() method removes empty slots in an array:

JavaScript Array Object