1. let arr = ["A", "B", "C"];
    2. console.log(arr[0]); //A
    4. for (let item of Object.keys(arr)) {
    5.     console.log(item);  // 0 1 2
    6. }
    8. for (let item of Object.values(arr)) {
    9.     console.log(item);   // A B C
    10. }
    12. for (let temp of Object.entries(arr)) {
    13.     console.log(temp);  //(2) ['0', 'A'] ['1', 'B'] ['2', 'C']
    14. }