解释原型继承如何工作

// Parent object constructor.
function Animal(name) {
  this.name = name;
}

// Add a method to the parent object's prototype.
Animal.prototype.makeSound = function () {
  console.log('The ' + this.constructor.name + ' makes a sound.');
};

// Child object constructor.
function Dog(name) {
  Animal.call(this, name); // Call the parent constructor.
}

// Set the child object's prototype to be the parent's prototype.
Object.setPrototypeOf(Dog.prototype, Animal.prototype);

// Add a method to the child object's prototype.
Dog.prototype.bark = function () {
  console.log('Woof!');
};

// Create a new instance of Dog.
const bolt = new Dog('Bolt');

// Call methods on the child object.
console.log(bolt.name); // "Bolt"
bolt.makeSound(); // "The Dog makes a sound."
bolt.bark(); // "Woof!"