In order to inherit the prototype methods from Animal, we need to use Object.create to create a new object that inherits from Animal.prototype and assign it to Dog.prototype.

function Animal(name) {
  this.name = name;
}

Animal.prototype.speak = function() {
  console.log(this.name + ' makes a noise.');
}

function Dog(name) {
  Animal.call(this, name);
}

Dog.prototype = Object.create(Animal.prototype);

const dog = new Dog('Rex');

dog.speak();