RockPaperAaron.js

rps.js

var options = [ "rock", "paper", "scissors" ];
var results = [ "wins!", "loses!", "draws!" ];

var compare = {
  rock: { 
    rock: 2,
    paper: 0,
    scissors: 1
  },
  paper: {
    rock: 1,
    paper: 2,
    scissors: 0
  },
  scissors: {
    rock: 0,
    paper: 1,
    scissors: 2
  } 
};

var computerChoice = options[Math.floor(Math.random() / 0.33)];
var userChoice = prompt('Do you choose rock, paper or scissors?');
// Let's assume input has been validated :)
var result = compare[userChoice][computerChoice];

console.log(userChoice + ' ' + results[result]);