Run results for: simple instanceof vs. getter vs. instance property

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.5 Safari/605.1.15

Browser: Safari 18

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 9 months ago

Test name	Executions per second
instance	81562.4 Ops/sec
getter	96214.4 Ops/sec
instance property	85101.6 Ops/sec

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

class ExampleClass {
    get isExampleGetter() {
        return true;
    }

    isExampleField = true;
}

const items = Array.from({
    length: 10000
}, (_) => new ExampleClass());

Tests:

instanceof
let validCount = 0; for (const i of items) { if (i instanceof ExampleClass) { validCount += 1; } } console.log(validCount);
getter
let validCount = 0; for (const i of items) { if (i.isExampleGetter) { validCount += 1; } } console.log(validCount);
instance property
let validCount = 0; for (const i of items) { if (i.isExampleField) { validCount += 1; } } console.log(validCount);

Run results for: simple instanceof vs. getter vs. instance property

Compare the basic performance of different ways of checking whether a given item is an instance of a specific class.

instanceof

getter

instance property