How do I put this if statement into a function correctly?

I am trying to put the if else code below into a function:

 if (randomnum == 1) {
      var codes = ["qjyreu", "achin", "eralnrde", "hiwel", "eW", "ni"];
      var words = ["jquery", "china", "learned", "while", "We", "in"];
      var finalAnswer = "Welearnedjquerywhileinchina";
    } else if (randomnum == 2) {
      var codes = ["oegs", "yob", "nignadc", "hTe", "ightn", "veery"];
      var words = ["goes", "boy", "dancing", "The", "night", "every"];
      var finalAnswer = "Theboygoesdancingeverynight";
    }

For reference, the randomnum is defined in the function rando:

function rando() {
  return (randomnum = Math.floor(Math.random() * 2) + 1);
}
rando();

Everytime I try and put my if else statement into a function and call it, the console says: codes not defined. I just want to to successfully put my if else statment into a function that I can call.