one-second.js

/**
 * "One second".
 *
 * Since 1967, the sample value of One Second is:
 *
 * "The duration of 9,192,631,770 periods of the radiation corresponding
 *  to the transition between the two hyperfine levels of the ground state
 *  of the caesium-133 atom."
 *
 * by Dmitry Soshnikov <[email protected]>
 * MIT Style License.
 */

// -----------------------------------------------------------
// 1. An atom of Caesium-133.
// -----------------------------------------------------------

var Caesium133Atom = {
  _radiationPeriods: 0,
  _TRANSITION_RADIATION_PERIODS: 9192631770,

  // ☢ Let's do some radiation
  radiate: function() {
    this._radiationPeriods++;
    // When we reached this number of radiation periods,
    // we transit (change energy level).

    // Ha-ha. Sorry, it will be soooooo long waiting while this number of
    // periods can be reached in your JS engine, so for real tests
    // just set _TRANSITION_RADIATION_PERIODS to e.g. 10.
    if (this._radiationPeriods == this._TRANSITION_RADIATION_PERIODS) {
      this._transitBetweenTwoHyperfineLevels();
      this._radiationPeriods = 0;
    }
    setTimeout(this.radiate.bind(this), 0);
  },

  // Out transition time is taken as a Sample value
  // of One second; inform about it.
  _transitBetweenTwoHyperfineLevels: function() {
    this._transitionObserver();
  },

  registerTransitionObserver: function(transitionObserver) {
    this._transitionObserver = transitionObserver;
  }
};

Caesium133Atom.radiate();

// -----------------------------------------------------------
// 2. One Second determination process, and time counting.
// -----------------------------------------------------------

var seconds = 0;

// Connect to caesium-133 atom that will inform us when one
// second is passed.
Caesium133Atom.registerTransitionObserver(function() {
  console.log('Time is:', getTime(++seconds));
});

function getTime(seconds) {
  var minutes = Math.floor(seconds / 60);
  var hours = Math.floor(minutes / 60);
  return hours + 'h, ' + minutes + 'm, ' + (seconds % 60);
}