EventCounts
Baseline
2025
Newly available
Since December 2025, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.
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.sizefor 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
| Specification |
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| Event Timing API # sec-event-counts |
Browser compatibility
| desktop | mobile | |||||||||||
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EventCounts
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get
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values
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Legend
Tip: you can click/tap on a cell for more information.
- Full support
- Full support