PerformanceObserverEntryList

The PerformanceObserverEntryList interface is a list of performance events that were explicitly observed via the observe() method.

Instance methods

PerformanceObserverEntryList.getEntries()

Returns a list of all explicitly observed PerformanceEntry objects.

PerformanceObserverEntryList.getEntriesByType()

Returns a list of all explicitly observed PerformanceEntry objects of the given entry type.

PerformanceObserverEntryList.getEntriesByName()

Returns a list of all explicitly observed PerformanceEntry objects based on the given name and entry type.

Example

Using PerformanceObserverEntryList

In the following example, list is the PerformanceObserverEntryList object. The getEntries() method is called to get all explicitly observed PerformanceEntry objects which are "measure" and "mark" in this case.

js
function perfObserver(list, observer) {
  list.getEntries().forEach((entry) => {
    if (entry.entryType === "mark") {
      console.log(`${entry.name}'s startTime: ${entry.startTime}`);
    }
    if (entry.entryType === "measure") {
      console.log(`${entry.name}'s duration: ${entry.duration}`);
    }
  });
}
const observer = new PerformanceObserver(perfObserver);
observer.observe({ entryTypes: ["measure", "mark"] });

Specifications

Specification
Performance Timeline
# performanceobserverentrylist-interface

Browser compatibility

desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
Deno
Node.js
PerformanceObserverEntryList
getEntries
getEntriesByName
getEntriesByType