Note: This feature is available in Web Workers
The PerformanceObserver
interface is used to observe performance measurement events and be notified of new performance entries as they are recorded in the browser's performance timeline.
Note: This feature is available in Web Workers
The PerformanceObserver
interface is used to observe performance measurement events and be notified of new performance entries as they are recorded in the browser's performance timeline.
PerformanceObserver()
Creates and returns a new PerformanceObserver
object.
PerformanceObserver.supportedEntryTypes
Read only
Returns an array of the entryType
values supported by the user agent.
PerformanceObserver.observe()
Specifies the set of entry types to observe. The performance observer's callback function will be invoked when performance entry is recorded for one of the specified entryTypes
.
PerformanceObserver.disconnect()
Stops the performance observer callback from receiving performance entries.
PerformanceObserver.takeRecords()
Returns the current list of performance entries stored in the performance observer, emptying it out.
The following example creates a PerformanceObserver
watching for "mark" (PerformanceMark
) and "measure" (PerformanceMeasure
) events. The perfObserver
callback provides a list
(PerformanceObserverEntryList
) which allows you to get observed performance entries.
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"] });
Specification |
---|
Performance Timeline # dom-performanceobserver |
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
PerformanceObserver |
52 | 79 | 57 | No | 39 | 11 | 52 | 52 | 57 | 41 | 11 | 6.0 |
PerformanceObserver |
52 | 79 | 57 | No | 39 | 11 | 52 | 52 | 57 | 41 | 11 | 6.0 |
disconnect |
52 | 79 | 57 | No | 39 | 11 | 52 | 52 | 57 | 41 | 11 | 6.0 |
observe |
52 | 79 | 57 | No | 39 | 11 | 52 | 52 | 57 | 41 | 11 | 6.0 |
supportedEntryTypes_static |
73 | 79 | 68 | No | 60 | 13 | 73 | 73 | 68 | 52 | 13 | 11.0 |
takeRecords |
65 | 79 | 60 | No | 52 | 15 | 65 | 65 | 60 | 47 | 15 | 9.0 |
worker_support |
62 | 79 | 57 | No | 49 | 11 | 62 | 62 | 57 | 46 | 11 | 8.0 |
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https://developer.mozilla.org/en-US/docs/Web/API/PerformanceObserver