NodeJS Measure Execution Time

testMeasureTime.js

/**
 * @param {String} [str]
 */
const logTime = (() => {
	let hrstart, hrend;
	return str => {
		if (hrstart === undefined) {
			hrstart = process.hrtime();
			return;
		}

		hrend = process.hrtime(hrstart);
		console.info((str === undefined ? '' : `${str} - `) + '%ds %dms', hrend[0], hrend[1] / 1000000);
		hrstart = process.hrtime();
	};
})();

function test() {
  // Start timer
  logTime();
  let sum = 0;
  for (let i = 0; i < 1e6; i++) {
    sum += Math.random();
  }
  
  // Ending first timer, also serves as start for next log
  logTime('Label 1');
  
  sum = 0;
  for (let i = 0; i < 1e9; i++) {
    sum += Math.random();
  }
  
  // Uses `Label 1` timer as start
  logTime('Label 2');
}

test(); // Logs:
//
//         Label 1 - 0s 12.12315ms
//         Label 2 - 8s 184.500578ms