Javascript原型继承和"instanceof“

function safeInstanceOf(obj, constructor) {
  if (typeof constructor !== 'function') {
    throw new TypeError('Right-hand side of instanceof is not callable');
  }
  let prototype = constructor.prototype;
  let currentProto = Object.getPrototypeOf(obj);
  while (currentProto) {
    if (currentProto === prototype) {
      return true;
    }
    currentProto = Object.getPrototypeOf(currentProto);
  }
  return false;
}

function Parent() {
  this.name = 'Parent';
}

Parent.prototype.sayHello = function() {
  console.log('Hello from Parent');
};

function Child() {
  this.name = 'Child';
}

Child.prototype = Object.create(Parent.prototype);
Child.prototype.constructor = Child;

Child.prototype.sayHello = function() {
  console.log('Hello from Child');
};

const child = new Child();
console.log(child.name); // Child
child.sayHello(); // Hello from Child