EventCounts

The EventCounts interface is a read-only map where the keys are event types and the values are the number of events that have been dispatched for that event type.

As a read-only map, EventCounts is similar to a Map, however, it doesn't implement the clear(), delete(), and set() methods.

Constructor

This interface has no constructor. You typically get an instance of this object using the performance.eventCounts property.

Instance properties

size: See Map.prototype.size for details.

Instance methods

entries(): See Map.prototype.entries() for details.
forEach(): See Map.prototype.forEach() for details.
get(): See Map.prototype.get() for details.
has(): See Map.prototype.has() for details.
keys(): See Map.prototype.keys() for details.
values(): See Map.prototype.values() for details.

Examples

Working with EventCount maps

Below are a few examples to get information from an EventCounts map. Note that the map is read-only and the clear(), delete(), and set() methods aren't available.

for (entry of performance.eventCounts.entries()) {
  const type = entry[0];
  const count = entry[1];
}

const clickCount = performance.eventCounts.get("click");

const isExposed = performance.eventCounts.has("mousemove");
const exposedEventsCount = performance.eventCounts.size;
const exposedEventsList = [...performance.eventCounts.keys()];

Specifications

Specification
Event Timing API # sec-event-counts

Browser compatibility

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