const monster1 = {
  eyeCount: 4
};

const handler1 = {
  getOwnPropertyDescriptor(target, prop) {
    console.log(`called: ${prop}`);
    // expected output: "called: eyeCount"

    return { configurable: true, enumerable: true, value: 5 };
  }
};

const proxy1 = new Proxy(monster1, handler1);

console.log(Object.getOwnPropertyDescriptor(proxy1, 'eyeCount').value);
// expected output: 5