JAVASCRIPT

how to concatenate two arrays

int[] z = x.Concat(y).ToArray();

A better way to concatenate arrays

let arr1 = [0, 1, 2];
let arr2 = [3, 4, 5];

arr1 = [...arr1, ...arr2];
//  arr1 is now [0, 1, 2, 3, 4, 5]
// Note: Not to use const otherwise, it will give TypeError (invalid assignment)

how to concatenate two arrays

var z = new int[x.Length + y.Length];
x.CopyTo(z, 0);
y.CopyTo(z, x.Length);

A better way to concatenate arrays

var a = [1, 2], b = ["x", "y"], c = [true, false];
var d = a.concat(b, c);
console.log(d); // [1, 2, "x", "y", true, false];