Lap NPM | npm.io

lap

JavaScript performance testing library for the browser or server

API

Methods

lap.time(laps, racers)
lap.speed(laps, racers)
lap.timestamp()

Parameters

laps refers to number of laps to run (positive integer)
racers refers to function(s) to race (array or single function)

Usage tips

Use JavaScript exponential notation like 1e3 (rather than 1000) for expressing large numbers
Accurate results require many laps. The ideal amount depends on how complex the racers are:
- Infinity speeds and 0 times both indicate inadequate laps
- Results taking too long indicates excessive laps. Use less laps or use the .async syntax

`lap.time(laps, racers)`

Time how long it takes each racer to run the given number of laps
@return array of times measured in milliseconds

`.time` example

lap.time(1e5, [
  function() { document.getElementById('example') },
  function() { document.querySelector('#example') },
  function() { document.querySelectorAll('#example')[0] }
]) // => [40.000000000873115, 44.99999999825377, 116.00000000180444]

`lap.speed(laps, racers)`

Estimate each racer's average speed over a course of laps
@return array of speeds measured in operations per second

`.speed` example

lap.speed(1e5, [
  function() { document.getElementById('example') },
  function() { document.querySelector('#example') },
  function() { document.querySelectorAll('#example')[0] }
]) // => [2500000.0004001777, 2222222.2219491494, 884955.7522315352]

`lap.timestamp()`

Get a hi-resolution timestamp
@return number measured in milliseconds

`.timestamp` example

lap.timestamp() // => 1610.000000000582

`.async`

Methods are callable .async with the same arguments plus a (err, result) callback
@return undefined

`.async` syntax

lap.time.async(laps, racers, callback)
lap.speed.async(laps, racers, callback)
lap.timestamp.async(callback)

`.async` example

lap.time.async(1e5, function() {
  [].concat([0, 1, 2, 3])
}, function(err, result) {
  err || console.log(result[0] + ' ms')
}) // => undefined

`.sync`

.sync methods are included for expressiveness but these are just aliases. lap.time === lap.time.sync etc.

`.sync` example

lap.time.sync(1e5, [
  function() { document.getElementById('example') },
  function() { document.querySelector('#example') },
  function() { document.querySelectorAll('#example')[0] }
]) // => [40.000000000873115, 45.99999999481952, 115.00000000523869]