scientist/lib/measurement.js

Carefully refactor critical paths in production

var Measurement, Stopwatch;

Stopwatch = (function() {
  function Stopwatch() {
    this.reset();
  }

  Stopwatch.prototype.reset = function() {
    return this._start = process.hrtime();
  };

  Stopwatch.prototype.time = function() {
    return this._hrToMs(process.hrtime(this._start));
  };

  Stopwatch.prototype._hrToMs = function(arg) {
    var nanoseconds, seconds;
    seconds = arg[0], nanoseconds = arg[1];
    return Math.round(seconds * 1e3 + nanoseconds / 1e6);
  };

  return Stopwatch;

})();

Measurement = (function() {
  function Measurement(stopwatch) {
    this._stopwatch = stopwatch;
    this.elapsed = stopwatch.time();
    Object.freeze(this);
  }

  Measurement.benchmark = function(block) {
    var stopwatch;
    stopwatch = new Stopwatch();
    block();
    return new Measurement(stopwatch);
  };

  Measurement.prototype.remeasure = function(block) {
    block();
    return new Measurement(this._stopwatch);
  };

  Measurement.prototype.preserve = function(block) {
    block();
    return this;
  };

  return Measurement;

})();

module.exports = Measurement;