let arr = [1,2,3,4,5]

arr.concat(6)

console.log(arr)
// Expected output: [1,2,3,4,5]

let arrClone = arr.concat("I am six")

console.log(arrClone)
// Expected output: [1,2,3,4,5, "I am six"]

console.log(arr)
// Expected output: [1,2,3,4,5]