How to merge or combine arrays in JavaScript

by Sai gowtham1min read

In JavaScript there are manyways to merge or combine arrays let’s learn the most commonly used methods to merging arrays.

Array.Concat( ) method

JavaScript concat method creates the new array by merging two or more arrays instead of mutating the existing arrays.

const num1  = [1,2,3,4];
const num2 = [5,6,7,8];

console.log(event.concat(odd))

// [1,2,3,4,5,6,7,8]

Merging three arrays

const num1 = [1,2,3];
const num2 = [4,5,6];
const num3 = [7,8,9];

console.log(num1.concat(num2,num3));

// [1,2,3,4,5,6,7,8,9]

Spread operator

We can also use JavaScript spread(…) operator to merge arrays.

const num1  = [1,2,3,4];
const num2 = [5,6,7,8];

console.log([...num1,...num2]);

// [1,2,3,4,5,6,7,8,9]

For loops

We can also merge arrays by using the loops.

const  num1  = [1,2,3,4];
const num2 = [5,6,7,8];


for (let n of num2){

  num1.push(n)

}

console.log(num1)

// [1, 2, 3, 4, 5, 6, 7, 8]

In the above code, we changed the existing array numbers by pushing the num2 array elements.