Simple rock, paper, scissors game.

gistfile1.js

/// include required lib
var readline = require('readline');


/// Generate computer answer
var ComputerAns = function(){
    var num = Math.random();
    //console.log(num);
    if (num < 0.34) return 'rock';
    if (num >= 0.34 && num < 0.67) return 'paper';
    if (num >= 0.67) return 'scissors';
};

/// Show Compared result
var Result = function(yourAns, compAns){
    if (yourAns === compAns) return 'tie!';

    if (yourAns === 'rock' &&  compAns === 'scissors') return 'You Win!';
    if (yourAns === 'scissors' &&  compAns === 'rock') return 'Computer Win!';
    
    if (yourAns === 'paper' &&  compAns === 'rock') return 'You Win!';
    if (yourAns === 'rock' &&  compAns === 'paper') return 'Computer Win!';
    
    if (yourAns === 'scissors' &&  compAns === 'paper') return 'You Win!';
    if (yourAns === 'paper' &&  compAns === 'scissors') return 'Computer Win!';
};

/// Print your answer, computer answer, and compared result
var CompareWithComputer = function(yourAns){
    var compAns = ComputerAns();

    console.log('-------------------------------------------');
    console.log('your choice is ', yourAns);
    console.log('computer choice is ',compAns); 
    console.log(Result(yourAns, compAns));
    console.log('------------------------------------------- \n');
};


/// Create a Command Line  Interface to let user key in value and show value in console.

var rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
});

// Set and show prompt
rl.setPrompt('Do you choose rock, paper or scissors?  ');
rl.prompt();

// check the line input
rl.on('line', function(line){
    switch(line.trim()){
        case 'rock':
            CompareWithComputer('rock');
            break;
        case 'paper':
            console.log('good choice!');
            break;
        case 'scissors':
            console.log('good choice!');
            break;
        default:
            console.log('You answer is `'+ line.trim() + 
                '`, please choose rock, paper, or scissors \n');
            break;
    }
    rl.prompt();
}).on('close', function(){
    console.log('\n\n ByeBye !  Have a nice day!\n\n');
    process.exit();
});