JavaScript ES6 – Array concat method

The JavaScript concat() method is used to merge two or more arrays. This method does not change the existing arrays, but instead returns a new array.

Think of JavaScript array concat() method as: “I want to combine 2 or more arrays into one array.”

array concat() parameters

JavaScript array concat() method consists of following parameters:

• arrayN – number of arrays to combine to, comma separated array names

Let’s see an example on how to use JavaScript array concat() method:

const letters = ['a', 'b', 'c'];
const numbers = [1, 2, 3];

const alphaNumeric = letters.concat(numbers);
console.log(alphaNumeric);

// OUTPUT
// [a', 'b', 'c', 1, 2, 3]

use concat() with multiple arrays

How to concatenate or combine multiple arrays in JavaScript?

To concatenate more than 1 JavaScript arrays we use concat() method.  It accept 1 or more array as arguments, it combines and returns them as a single array.

const arr1 = [5, 9, 2];
const arr2 = [1, 3, 5];
const arr3 = [11, 8, 21];

const combined = arr1.concat(arr2, arr3);
console.log(combined);

// OUTPUT
// [5, 9, 2, 1, 3, 5, 11, 8, 21]

array concat() usage and tips

• Use concat() method to combine 1 or more arrays
• concat() combines array and returns the as new array