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

Answer & Solution

Answer: Option A
Solution:
Object.assign(target, ...sources) copies properties from one or more source objects to a target object.
Related Questions on Average

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

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 do you define a method in a constructor function?

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

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

C). this.methodName = () {}

D). this.methodName: () {}

What will car['make'] return if var car = {make: 'Ford', model: 'Mustang'};?

A). Ford

B). Mustang

C). Undefined

D). Error

What does Object.keys(obj) return?

A). An array of the values of the object's properties

B). An array of the names of the object's properties

C). The first key of the object

D). The number of properties in the object

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

How do you add a new property to an existing object in JavaScript?

A). object.property = value;

B). object->property = value;

C). object:property = value;

D). object.addProperty('property', value);

What will the following code output? console.log(car.make); if var car = {make: 'Honda', model: 'Civic'};

A). Honda

B). Civic

C). Undefined

D). Error

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() {} }