The getEntriesByType()
method of the PerformanceObserverEntryList
returns a list of explicitly observed performance entry objects for a given performance entry type. 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).
A list of explicitly observed PerformanceEntry
objects that have the specified type
. The items will be in chronological order based on the entries' startTime
. If no objects have the specified type
, or no argument is provided, an empty list is returned.
The following example shows the difference between the getEntries()
, getEntriesByName()
, and getEntriesByType()
methods.
const observer = new PerformanceObserver((list, obs) => {
let perfEntries = list.getEntries();
perfEntries.forEach((entry) => {
console.log(`${entry.name}'s duration: ${entry.duration}`);
});
perfEntries = list.getEntriesByName("debugging", "measure");
perfEntries.forEach((entry) => {
console.log(`${entry.name}'s duration: ${entry.duration}`);
});
perfEntries = list.getEntriesByType("mark");
perfEntries.forEach((entry) => {
console.log(`${entry.name}'s startTime: ${entry.startTime}`);
});
});
observer.observe({
entryTypes: ["mark", "measure", "navigation", "resource"],
});