array concat in javascript

let arr1 = [0, 1, 2];
let arr2 = [3, 5, 7];
let primes = arr1.concat(arr2);

// > [0, 1, 2, 3, 5, 7]//for ES5
var array1 = ["Rahul", "Sachin"];
var array2 = ["Sehwag", "Kohli"];

var output = array1.concat(array2);
console.log(output);

//for ES6, we use spread operators to concat arrays

var array1 = ["Dravid", "Tendulkar"];
var array2 = ["Virendra", "Virat"];

var output = [...array1, ...array2];
console.log(output);
const array1 = ['a', 'b', 'c'];
const array2 = ['d', 'e', 'f'];
const array3 = array1.concat(array2);

console.log(array3);
// expected output: Array ["a", "b", "c", "d", "e", "f"]const letters = ['a', 'b', 'c'];
const numbers = [1, 2, 3];

letters.concat(numbers);
// result in ['a', 'b', 'c', 1, 2, 3]
const letters = ['a', 'b', 'c'];
const numbers = [1, 2, 3];

const newArray = letters.concat(numbers);
// newArrat is ['a', 'b', 'c', 1, 2, 3]// using push and apply to return the same array
const arr1 = ['a', 'b'];
const arr2 = ['c', 'd'];
arr1.push.apply(arr1, arr2);
console.log(arr1) // ['a', 'b', 'c', 'd']