Symbol.toStringTag

class ValidatorClass {
  get [Symbol.toStringTag]() {
    return "Validator";
  }
}

console.log(Object.prototype.toString.call(new ValidatorClass()));
// Expected output: "[object Validator]"

Object.prototype.toString.call("foo"); // "[object String]"
Object.prototype.toString.call([1, 2]); // "[object Array]"
Object.prototype.toString.call(3); // "[object Number]"
Object.prototype.toString.call(true); // "[object Boolean]"
Object.prototype.toString.call(undefined); // "[object Undefined]"
Object.prototype.toString.call(null); // "[object Null]"
// ... and more

Object.prototype.toString.call(new Map()); // "[object Map]"
Object.prototype.toString.call(function* () {}); // "[object GeneratorFunction]"
Object.prototype.toString.call(Promise.resolve()); // "[object Promise]"
// ... and more

class ValidatorClass {}

Object.prototype.toString.call(new ValidatorClass()); // "[object Object]"

class ValidatorClass {
  get [Symbol.toStringTag]() {
    return "Validator";
  }
}

Object.prototype.toString.call(new ValidatorClass()); // "[object Validator]"

const test = document.createElement("button");
test.toString(); // Returns [object HTMLButtonElement]
test[Symbol.toStringTag]; // Returns HTMLButtonElement