JavaScript Array concat()

Join two arrays:

const arr1 = ["Cecilie", "Lone"];
const arr2 = ["Emil", "Tobias", "Linus"];
const children = arr1.concat(arr2);

Join three arrays:

const arr1 = ["Cecilie", "Lone"];
const arr2 = ["Emil", "Tobias", "Linus"];
const arr3 = ["Robin"];
const children = arr1.concat(arr2, arr3);

More examples below.

Description

The concat() method concatenates (joins) two or more arrays.

The concat() method returns a new array, containing the joined arrays.

The concat() method does not change the existing arrays.

array1.concat(array2, array3, ..., arrayX)

Parameter	Description
array1,...	Required. The array(s) to be concatenated.

Type	Description
Array	The content from the joined arrays.

Concatenate strings and numbers:

const arr1 = ["Cecilie", "Lone"];
const arr2 = [1, 2, 3];
const arr3 = arr1.concat(arr2);

Concatenate nested arrays:

const arr1 = [1, 2, [3, 4]];
const arr2 = [[5, 6], 7, 8];
const arr3 = arr1.concat(arr2);

concat() is an ECMAScript1 (ES1) feature.

ES1 (JavaScript 1997) is fully supported in all browsers:


Chrome	Edge	Firefox	Safari	Opera	IE
Yes	Yes	Yes	Yes	Yes	Yes