nanotiming overlapping timers

01_failing.js

// Three operations (loops for simplicity).
// We want to time the first two separately and all three of them together.
// Ideally, the ordering of starting the timers would not matter.

// This case fails because the timer for the first two loops is started first
var nanotiming = require('nanotiming')

try {
  var performance = require('perf_hooks').performance
  var timeFirstTwo = nanotiming('my-loop')
  var timeAll = nanotiming('my-loop')
} catch (e) {
  console.log('perf_hooks not available, exiting')
  process.exit(1)
}

var i = 10
while (--i) console.log(i)

var i = 10
while (--i) console.log(i)

timeFirstTwo()
reportTiming()

var i = 10
while (--i) console.log(i)

timeAll()
reportTiming()

function reportTiming() {
  var timings = performance.getEntries()
  // This assumes that the last one is the one we want
  var timing = timings[timings.length - 1]
  console.log(timing.name, timing.duration) // log the last entry
  performance.clearMeasures(timing.name)    // be a good citizen and free after use
}

02_succeeds.js

// This case succeeds because the timer for the first two loops is started last
var nanotiming = require('nanotiming')

try {
  var performance = require('perf_hooks').performance
  var timeAll = nanotiming('my-loop')
   var timeFirstTwo = nanotiming('my-loop')
} catch (e) {
  console.log('perf_hooks not available, exiting')
  process.exit(1)
}

var i = 10
while (--i) console.log(i)

var i = 10
while (--i) console.log(i)

timeFirstTwo()
reportTiming()

var i = 10
while (--i) console.log(i)

timeAll()
reportTiming()

function reportTiming() {
  var timings = performance.getEntries()
  // This assumes that the last one is the one we want
  var timing = timings[timings.length - 1]
  console.log(timing.name, timing.duration) // log the last entry
  performance.clearMeasures(timing.name)    // be a good citizen and free after use
}

03_with_name.js

// This case succeeds because the callback to stop timing
// gets the measure name, which means we can reference
// it with getEntriesByName(...)

// This requires a change to nanotiming line 34 to be 
// if (cb) cb(err, measureName)
var nanotiming = require('nanotiming')

// Three operations (loops for simplicity).
// We want to time the first two and all three of them.
// Ideally, the ordering of operations would not matter.
try {
  var performance = require('perf_hooks').performance
  // Start the timers
  // This fails:
  var timeFirstTwo = nanotiming('my-loop')
  var timeAll = nanotiming('my-loop')

  // This works:
  // var timeAll = nanotiming('my-loop')
  // var timeFirstTwo = nanotiming('my-loop')
} catch (e) {
  console.log('perf_hooks not available, exiting')
  process.exit(1)
}

var i = 10
while (--i) console.log(i)

var i = 10
while (--i) console.log(i)

timeFirstTwo(reportTiming)

var i = 10
while (--i) console.log(i)

timeAll(reportTiming)

function reportTiming(err, name) {
  // NOTE: name has to be the measurement name; this is not
  // currently the case with nanotiming.
  var timing = performance.getEntriesByName(name)[0]
  console.log(timing.name, timing.duration) // log the last entry
  performance.clearMeasures(timing.name)    // be a good citizen and free after use
}