Run results for: Instanceof vs string comparison vs property checking vs constructor comparison

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36

Browser: Chrome 135

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one month ago

HTML Preparation code:

<script>
class TestClass {
    constructor() {
        this.a = 2;
        this.t = 'mesh';
    }
}
</script>

AخA
 
<script>
class TestClass {
    constructor() {
        this.a = 2;
        this.t = 'mesh';
    }
}
</script>

Script Preparation code:

var obj = new TestClass();

 
var obj = new TestClass();

Tests:

instanceof
obj instanceof TestClass;
obj instanceof TestClass;
string type
obj.t === 'mesh'
obj.t === 'mesh'
string type + undefined
obj.t !== undefined
obj.t !== undefined
property
obj.a !== undefined
obj.a !== undefined
constructor comparison
obj.constructor === TestClass
obj.constructor === TestClass