PerformanceObserver

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.supportedEntryTypesRead 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 a 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.

function perf_observer(list, observer) {
   // Process the "measure" event
}
var observer2 = new PerformanceObserver(perf_observer);
observer2.observe({entryTypes: ["measure"]});

• MutationObserver
• ResizeObserver
• IntersectionObserver