JS原型链的面试题

题目1

function Person(name) {this.name = name;
}Person.prototype.greet = function() {console.log('Hello, my name is ' + this.name);
};function Student(name, grade) {Person.call(this, name);this.grade = grade;
}Student.prototype = Object.create(Person.prototype);
Student.prototype.constructor = Student;var john = new Student('John', 'Grade 10');
john.greet();

请问上述代码的输出结果是什么？

答案1

输出结果是：Hello, my name is John

题目2

function Animal(name) {this.name = name;
}Animal.prototype.sound = function() {console.log(this.name + ' makes a sound.');
};function Dog(name, breed) {Animal.call(this, name);this.breed = breed;
}Dog.prototype = Object.create(Animal.prototype);
Dog.prototype.constructor = Dog;var sparky = new Dog('Sparky', 'Golden Retriever');
sparky.sound();

请问上述代码的输出结果是什么？

答案2

输出结果是：Sparky makes a sound.

题目3

function Vehicle(type) {this.type = type;
}Vehicle.prototype.drive = function() {console.log('This ' + this.type + ' is driving.');
};function Car(type, model) {Vehicle.call(this, type);this.model = model;
}Car.prototype = Object.create(Vehicle.prototype);
Car.prototype.constructor = Car;var myCar = new Car('car', 'Toyota');
myCar.drive();

请问上述代码的输出结果是什么？

答案3

输出结果是：This car is driving.

题目4

function Fruit(name) {this.name = name;
}Fruit.prototype.describe = function() {console.log('This is a ' + this.name);
};function Apple(name, color) {Fruit.call(this, name);this.color = color;
}Apple.prototype = Object.create(Fruit.prototype);
Apple.prototype.constructor = Apple;var greenApple = new Apple('Green Apple', 'green');
greenApple.describe();

请问上述代码的输出结果是什么？

答案4

输出结果是：This is a Green Apple

题目5

function Shape() {this.type = 'shape';
}Shape.prototype.getType = function() {return 'Type: ' + this.type;
};function Triangle() {Shape.call(this);this.type = 'triangle';
}Triangle.prototype = Object.create(Shape.prototype);
Triangle.prototype.constructor = Triangle;var myTriangle = new Triangle();
console.log(myTriangle.getType());