PerformanceObserverEntryList: getEntriesByName() method

Available in workers

The getEntriesByName() method of the PerformanceObserverEntryList interface returns a list of explicitly observed PerformanceEntry objects for a given name and entryType. The list’s members are determined by the set of entry types specified in the call to the observe() method. The list is available in the observer’s callback function (as the first parameter in the callback).

Syntax

getEntriesByName(name)
getEntriesByName(name, type)

Parameters

• name
  • : A string representing the name of the entry to retrieve.
• type Optional
  • : A string representing the type of entry to retrieve such as "mark". The valid entry types are listed in entryType.

Return value

A list of explicitly observed performance entry objects that have the specified name and type. If the type argument is not specified, only the name will be used to determine the entries to return. The items will be in chronological order based on the entries’ startTime. If no objects meet the specified criteria, an empty list is returned.

Examples

Working with getEntries, getEntriesByName and getEntriesByType

The following example shows the difference between the getEntries(), getEntriesByName(), and getEntriesByType() methods.

const observer = new PerformanceObserver((list, obs) => {
  // Log all entries
  let perfEntries = list.getEntries();
  perfEntries.forEach((entry) => {
    console.log(`${entry.name}'s duration: ${entry.duration}`);
  });

  // Log entries named "debugging" with type "measure"
  perfEntries = list.getEntriesByName("debugging", "measure");
  perfEntries.forEach((entry) => {
    console.log(`${entry.name}'s duration: ${entry.duration}`);
  });

  // Log entries with type "mark"
  perfEntries = list.getEntriesByType("mark");
  perfEntries.forEach((entry) => {
    console.log(`${entry.name}'s startTime: ${entry.startTime}`);
  });
});

// Subscribe to various performance event types
observer.observe({
  entryTypes: ["mark", "measure", "navigation", "resource"],
});

Specifications

Browser compatibility