David Nguyen

Knowledge check: Introduction to Object-Oriented Programming in Javascript

Knowledge check: Introduction to Object-Oriented Programming in Javascript

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David Nguyen
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  1. What will print out when the following code runs?

     class Cake {
     constructor(lyr) {
         this.layers = lyr + 1;
     }
 }

 var result = new Cake(1);
 console.log(result.layers);

    • 1

    • 2

    • 3

    • 4

  2. When a class extends another class, this is called ____________.

    • Inheritance

    • Extension

  3. What will print out when the following code runs?

     class Animal {
     constructor(lg) {
         this.legs = lg;
     }
 }

 class Dog extends Animal {
     constructor() {
         super(4);
     }
 }

 var result = new Dog();
 console.log(result.legs);

    • 0

    • undefined

    • null

    • 4

  4. What will print out when the following code runs?

     class Animal {

 }

 class Cat extends Animal {
     constructor() {
     super();
     this.noise = "meow";
     }
 }

 var result = new Animal();
 console.log(result.noise);

    • undefined

    • null

    • ""

    • meow

  5. What will print out when the following code runs?

     class Person {
     sayHello() {
         console.log("Hello");
     }
 }

 class Friend extends Person {
     sayHello() {
         console.log("Hey");
     }
 }

 var result = new Friend();
 result.sayHello();

    • Hello

    • Hey

JavaScript