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EventCounts

The EventCounts interface of the Performance API provides the number of events that have been dispatched for each event type.

An EventCounts instance is a read-only Map-like object, in which each key is the name string for an event type, and the corresponding value is an integer indicating the number of events that have been dispatched for that event type.

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.

js

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

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
@@iterator 85 85 89 No 71 No 85 85 89 60 No 14.0
EventCounts 85 85 89 No 71 No 85 85 89 60 No 14.0
entries 85 85 89 No 71 No 85 85 89 60 No 14.0
forEach 85 85 89 No 71 No 85 85 89 60 No 14.0
get 85 85 89 No 71 No 85 85 89 60 No 14.0
has 85 85 89 No 71 No 85 85 89 60 No 14.0
keys 85 85 89 No 71 No 85 85 89 60 No 14.0
size 85 85 89 No 71 No 85 85 89 60 No 14.0
values 85 85 89 No 71 No 85 85 89 60 No 14.0

See also

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https://developer.mozilla.org/en-US/docs/Web/API/EventCounts