Q
What is encapsulation in the context of JavaScript objects?

Answer & Solution

Answer: Option A
Solution:
Encapsulation is a principle of hiding the internal state of an object and allowing modification through defined methods only.
Related Questions on Average

How do you define a method in a constructor function?

A). this.methodName = function() {}

B). this.methodName: function() {}

C). this.methodName = () {}

D). this.methodName: () {}

Which of the following correctly creates an instance of a Car object using a constructor function?

A). var myCar = Car('Toyota', 'Corolla', 2020);

B). var myCar = new Car('Toyota', 'Corolla', 2020);

C). var myCar = create Car('Toyota', 'Corolla', 2020);

D). var myCar = construct Car('Toyota', 'Corolla', 2020);

Which of the following is a correct way to define an object using an object literal?

A). var car = {make: 'Toyota', model: 'Corolla'};

B). var car = make: 'Toyota', model: 'Corolla';

C). var car = new Object(make: 'Toyota', model: 'Corolla');

D). var car = Object.create(make: 'Toyota', model: 'Corolla');

In JavaScript, what keyword is used to define a new object from a constructor function?

A). create

B). construct

C). new

D). object

What does Object.assign(target, ...sources) do?

A). Copies properties from sources to target

B). Compares properties between target and sources

C). Deletes properties in sources

D). Merges properties of sources into target and removes duplicates

What is the output of car.start() if var car = {start: function() {console.log('Car started');}};?

A). Car

B). started

C). Car started

D). Error

How can you iterate over all properties of an object?

A). for (var key of object)

B). for (var key in object)

C). for (var key with object)

D). for (var key over object)

How do you define a method inside a class in JavaScript ES6?

A). methodName() {}

B). this.methodName = function() {}

C). function methodName() {}

D). methodName: function() {}

Which method can be used to call a function defined within an object?

A). object.functionName();

B). object->functionName();

C). object::functionName();

D). object.callFunction('functionName');

How do you define a constructor function for a Car object?

A). function Car(make, model, year) { this.make = make; this.model = model; this.year = year; }

B). Car(make, model, year) { this.make = make; this.model = model; this.year = year; }

C). function create Car(make, model, year) { this.make = make; this.model = model; this.year = year; }

D). function construct Car(make, model, year) { this.make = make; this.model = model; this.year = year; }