PerformanceObserverEntryList

Available in workers

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.

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

Browser compatibility