js get random not in code example

Example: javascript random number generator

let replies = [
    "1",
    "2",
    "3",
    "4",
    "5",
    "6",
    "7",
    "8",
    "9",
    "10",
    "11",
    "12"
  ];

  let result = Math.floor(Math.random() * replies.length);