Super simple JavaScript execution timing

tiny-profiler.js

const microtime = (() => {
  const currentNano = () => {
    const [a, b] = process.hrtime()
    return a * 1000000000 + b
  }
  const nanoToMilli = (ns) => (ns / 1000000).toFixed(3)
  const markers = {
    '-1': currentNano()
  }
  return {
    mark(id = -1) {
      markers[id] = currentNano()
    },
    since(id = -1) {
      return nanoToMilli(currentNano() - markers[id])
    }
  }
})()


// Demo code

const log = (mt, message) => console.log(`[${mt}]`, message)
const { mark, since } = microtime

// Mark and since without an argument may be
// used to track and overwrite a single moment
mark()
log(since(), 'a')


// This will demonstrate named marks
mark('character-b')
setTimeout(() => log(since('character-b'), 'b'), 50)

setTimeout(() => log(since('character-c'), 'c'), 60)
mark('character-c')


/* Demo Output
  > [~0.050 ms]   a
  > [~50.000 ms]  b
  > [~60.000 ms]  c
*/