Benchmark: Event Listener Performance

Script Preparation code:

function calculatePrimes(iterations, multiplier) {
  var primes = [];
  for (var i = 0; i < iterations; i++) {
    var candidate = i * (multiplier * Math.random());
    var isPrime = true;
    for (var c = 2; c <= Math.sqrt(candidate); ++c) {
      if (candidate % c === 0) {
          // not prime
          isPrime = false;
          break;
       }
    }
    if (isPrime) {
      primes.push(candidate);
    }
  }
  return primes;
}

Tests:

Default Event
window.bus1 = window.document.createElement('main'); window.bus1.addEventListener('test1', (event) => { var primes = calculatePrimes(10, 1000000000); }); const event1 = new CustomEvent('test1'); if (window.bus1.dispatchEvent(event1)) { console.log('1'); }
Passive Event
window.bus2 = window.document.createElement('main'); window.bus2.addEventListener('test2', async (event) => { new Promise(() => { var primes = calculatePrimes(10, 1000000000) }); }, {passive: true}); const event2 = new CustomEvent('test2', { cancelable: false, }); if (window.bus2.dispatchEvent(event2)) { console.log('2'); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Default Event
Passive Event

Fastest: N/A

Slowest: N/A

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Latest run results:

Run details: (Test run date: 7 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.0.0 Safari/537.36

Browser/OS: Chrome 116 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Default Event	19.3 Ops/sec
Passive Event	19.4 Ops/sec

Event Listener Performance (version: 10)

Comparing performance of: Default Event vs Passive Event

Created: 3 years ago by: Registered User

Jump to the latest result

Default Event

Passive Event

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A