What is encapsulation in the context of JavaScript objects?
A). Hiding the internal state and requiring all interaction to be performed through an object's methods
B). Extending one object from another
C). Creating a new object
D). Removing a property from an 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() {}
How do you define a class in JavaScript ES6?
A). class ClassName { constructor() {} }
B). function ClassName() { constructor() {} }
C). class ClassName() { constructor {} }
D). function class ClassName { constructor() {} }
What is the purpose of the this keyword in an object method?
A). It refers to the global object.
B). It refers to the current object.
C). It refers to the parent object.
D). It refers to the previous object.
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);
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)
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
What will car['make'] return if var car = {make: 'Ford', model: 'Mustang'};?
A). Ford
B). Mustang
C). Undefined
D). Error
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');
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