var audio = document.createElement("audio");
function andAOne(e){
e.count = (e.count|| 0) +1;
}
function andAOneAndAStop(e){
e.count = (e.count|| 0) +1;
e.count === 501 && e.stopPropagationImmediately();
}
for (var i = 0; i <1000; i++)
audio.addEventListener("ratechange",andAOne.bind({}));
audio.playbackRate = 2;
for (var i = 0; i <1000; i++)
audio.addEventListener("ratechange",andAOneAndAStop.bind({}));
audio.playbackRate = 2;
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
running async 1000 event listeners | |
running async 501 event listeners |
Test name | Executions per second |
---|---|
running async 1000 event listeners | 1.9 Ops/sec |
running async 501 event listeners | 0.7 Ops/sec |
Benchmark Overview
The provided benchmark measures the cost of adding multiple event listeners to an HTML5 audio element. The test cases compare two scenarios: adding 1000 asynchronous event listeners and adding 501 asynchronous event listeners.
Test Case 1: Running Async 1000 Event Listeners
In this test case, a loop is executed 1000 times, adding an event listener for the "ratechange" event to the audio element. The event listener function andAOne
increments a counter variable on each event trigger. The test measures the time it takes to execute this loop.
Test Case 2: Running Async 501 Event Listeners
Similar to Test Case 1, but with only 501 event listeners added in the loop.
Comparison of Approaches
The benchmark compares two approaches:
stopPropagationImmediately
method is called on the event object, which stops the event from propagating to other listeners.Pros and Cons
Pros:
Cons:
Library and Purpose
The stopPropagationImmediately
method is a native browser API that stops the propagation of an event from the current target element to all other elements in the DOM. In this benchmark, it's used to simulate a scenario where events are stopped after reaching a certain number of listeners.
Special JS Feature or Syntax
This benchmark does not use any special JavaScript features or syntax beyond standard ECMAScript 2015 (ES6) support. The focus is on measuring the performance impact of event listener additions rather than exploring advanced JavaScript concepts.
Alternatives
Other alternatives to measure the cost of adding event listeners could include:
XMLHttpRequest
or Fetch
) could provide insights into the performance impact of handling asynchronous events.By exploring these alternatives, developers can gain a deeper understanding of the factors influencing event listener performance and make informed decisions when optimizing their web applications.