Run results for: instanceof vs in options

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:138.0) Gecko/20100101 Firefox/138.0

Browser: Firefox 138

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
instanceof test	157504400.0 Ops/sec
in test	1553290624.0 Ops/sec
instanceof test again	160112240.0 Ops/sec
proper type check	1387363968.0 Ops/sec
includes check	45093188.0 Ops/sec

Script Preparation code:

class ClassFoo {
    constructor() {
        this.bar = 'classFoo';
    }
}

var knownTypes = ['otherClass', 'classFoo'];
var Foo = ClassFoo;
var foo = new Foo();

Tests:

instanceof test
foo instanceof Foo
in test
'bar' in foo
instanceof test again
foo instanceof Foo
proper type check
'bar' in foo && (foo.bar === 'otherClass' || foo.bar === 'classFoo')
includes check
'bar' in foo && knownTypes.includes(foo.bar)

Run results for: instanceof vs in options

instanceof test

in test

instanceof test again

proper type check

includes check