function solution(a, b) {

    return a.concat(b);

}

const letters = ['a', 'b', 'c'];

const numbers = [1, 2, 3];

​

const newArray = letters.concat(numbers);

// newArrat is ['a', 'b', 'c', 1, 2, 3]

//ES6

const array3 = [...array1, ...array2];

var array1 = ["Vijendra", "Singh"];

var array2 = ["Singh", "Shakya"];

​

console.log(array1.concat(array2));

const arrFirst = ['string1', 'string2'];

const arrSecond = ['string3','string4'];

​

const newArr = [...arrFirst, ...arrSecond];

​

console.log(newArr);

let arr1 = ['1', '2'];

let arr2 = ['3', '4'];

​

let combarr = [].concat(arr1); //define new variable, empty array then concatenating arr1 to it

combarr = combarr.concat(arr2); //combarr = itself, then concatenating arr2 to the end

console.log(combarr); //Expected output: ['1','2','3','4']

const array1 = ["Vijendra","Singh"];

const array2 = ["Singh", "Shakya"];

const array3 = [...array1, ...array2];

// [ "Vijendra", "Singh", "Singh", "Shakya" ]

[1,2,3].concat([4,5,6])

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

const fruits = ['apple', 'orange', 'banana'];

const joinedFruits = fruits.join();

​

console.log(joinedFruits); // apple,orange,banana

const letters = ['a', 'b', 'c'];

const numbers = [1, 2, 3];

​

letters.concat(numbers);

// result in ['a', 'b', 'c', 1, 2, 3]

​

const myGirls = ["Cecilie", "Lone"];

const myBoys = ["Emil", "Tobias", "Linus"];

​

const myChildren = myGirls.concat(myBoys);