Pfthb

This is my example code

const _performance = require('perf_hooks').performance;

someFunction= ()=>

 _performance.mark('mark A')

 // Do something
 const a= Array(100000)
 var boo =true;
 a.forEach(el=>
 boo = ! boo
 )

 _performance.mark('mark B')
 _performance.measure('total','mark B','mark A');

 var measurments = _performance.getEntriesByType('measure');

 measurments.forEach(measurment =>
 console.log(measurment.name + ' ' + measurment.duration)
 )



someFunction();

It crashes with the error message

TypeError: _performance.getEntriesByType is not a function

Any idea why is this happening?
I am using node v10.7.0 on windows 10

As of the latest perf_hooks API, the getEntriesByType() function is a method fo PerformanceObserverEntryList. Try this instead:

const performance, PerformanceObserver = require('perf_hooks')

const obs = new PerformanceObserver((items) ⇒ 

 items.getEntries().forEach((item) ⇒ 
 console.log(item.name, + ' ' + item.duration)
 )
)
obs.observe(entryTypes: ['measure'])


function someFunction() 
 // Do something
 const a = Array(100000)
 var boo =true;
 a.forEach(el⇒
 boo = ! boo

 )


performance.mark('mark A')
someFunction();
performance.mark('mark B')
performance.measure('total','mark A','mark B');