SOURCE

function instanceOf(left, right) {
	const proto = Object.getPrototypeOf(left), prototype = right.prototype;
    if (proto === null || proto === undefined) {
        return false;
    } else if (proto === prototype) {
        return true
    } else {
        return instanceOf(Object.getPrototypeOf(proto), right);
    }

}

var a = {};
var b = 2;
console.log(instanceOf(a, Object));
console.log(instanceOf(a, Object));
console.log(instanceOf(b, Object));
console.log(b instanceof Object);
console.log(instanceOf(Object, Function));
console.log(Object instanceof Function);