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

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:137.0) Gecko/20100101 Firefox/137.0

Browser: Firefox 137

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: one year ago

getter

43K/s

instance property

42K/s

instance

27K/s

View exact numbers

Test name	Executions per second
✓ getter	43,070 Ops/sec
instance property	42,094 Ops/sec
instance	27,481 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