PerformanceObserver.observe()

The observe() method of the PerformanceObserver interface is used to specify the set of performance entry types to observe.

See PerformanceEntry.entryType for a list of entry types and PerformanceObserver.supportedEntryTypes for a list of entry types the user agent supports.

When a matching performance entry is recorded, the performance observer’s callback function—set when creating the PerformanceObserver—is invoked.

Inputs: options An object with the following possible members: buffered A boolean flag to indicate whether buffered entries should be queued into the observer’s buffer. Must be used only with the type option. durationThreshold A DOMHighResTimeStamp defining the threshold for PerformanceEventTiming entries. Defaults to 104ms and is rounded to the nearest of 8ms. Lowest possible threshold is 16ms. May not be used together with the entryTypes option. entryTypes An array of strings, each specifying one performance entry type to observe. May not be used together with the type, buffered, or durationThreshold options.