Timespan calculator

timeGents.js

#!/usr/bin/env node

// Calculators time difference, if you don't provide a 2nd arg it assumes you want the diff 
// between 1st arg and the current timestamp

var start, finish, delta, timeParts;

console.log("args: " + process.argv.length);

process.argv.forEach(function (val, index, array) {
    console.log(index + ': ' + val);
});

if (process.argv.length < 3) {
  console.log("please supply start time!");
  process.exit(1);
}

timeParts = process.argv[2].split(':');
start = new Date();
start.setHours(timeParts[0]);
start.setMinutes(timeParts[1]);

finish = new Date();
if (process.argv.length == 4) {
  timeParts = process.argv[3].split(':');
  finish.setHours(timeParts[0]);
  finish.setMinutes(timeParts[1]);
}

delta = new Date(finish - start);

console.log("start: %s\nfinish: %s\nspan: %s"
    ,start.toLocaleTimeString()
    ,finish.toLocaleTimeString()
    ,delta.toLocaleTimeString());