performance


Simple performance benchmarking tools (browser and node)

Precise time measurement

#### var t = time(startTime)

When called without arguments, returns the current time as precisely as possible as a number of milliseconds or an array ([milliseconds, microseconds])

When called with an argument, returns the difference between the current time and the time passed in as argument, in milliseconds
- startTime (number|array) - start time for elapsed time calculation
- returns (number|array) t - Current time (in milliseconds) or elapsed time since startTime

``javascript
var time = require('vigour-performance').time
var startTime = time()
var elapsedTime = time(startTime)
`

Measuring a function's performance




#### run(subject, callback, nbIterations)
- subject (function) - the function to measure
- callback (function) - called when the measurement is done : callback(averageRunTime, nbIterations)
- nbIterations (number) - number of times to execute the subject function

`javascript
var run = require('vigour-performance').run
run(
() => {
// function to measure (subject)
},
(average, iterations) => {
// callback
// average : subject function average run time in milliseconds,
// iterations : number of times the subject function was executed
// )
},
100 // number of times to execute the subject function
)
`

Comparing functions




#### perf(subject, reference, margin, loop, subjectLabel, referenceLabel)
- subject (function) - function to measure
- reference (function) - function to compare with subject
- margin (number) - number of times faster subject must be compared to reference for the test to pass
- loop (number) - Number of times to run the functions (default: 10)
- subjectLabel (string) - Label for the subject function (default: the name of the function (subject.name))
- referenceLabel (string) - Label for the reference function (default: the name of the function (reference.name))

Uses tape internally, which produces TAP(Test Anything Protocol) output.

`javascript
var perf = require('vigour-performance')
// The following test will pass if subject executes at least 2 times as fast as reference
perf(function subject () {}, function reference () {}, 2)
``