Tail Recursion to infinite timed loop in Node.js... with Closures!

timed-loop-closure.js

function loop() {
  var start_date = Date.now()
  var old_date = start_date
  var seconds_running = 120
  
  var intervalId = setInterval(1000, function() {
    new_date = Date.now()
    
    // Execute this for just 30 seconds
    if( (new_date - start_date) < 1000 * seconds_running) {    
      var diff_tick = new_date - old_date  
      console.log('tick with difference : ' + diff_tick)
      old_date = new_date
    }
    else {
      console.log('Reached ' + seconds_running +' seconds at: ' + Date() )
      clearInterval(intervalId);
    }
  });
}

loop();