What does Object.keys(obj) return?

How can you remove a property 'email' from an obj...

A). delete user.email;

B). user.remove('email');

C). user.email = null;

D). user.pop('email');

How do you iterate over all properties of an obj...

A). for (var prop in person)

B). forEach(prop in person)

C). for (var prop of person)

D). forEach(prop of person)

What does the Object.values(obj) method return?

A). An array of object keys.

B). An array of object values.

C). An array of object properties.

D). An array of object methods.

How do you check if an object has a property 'col...

A). 'color' in obj

B). obj.hasProperty('color');

C). obj.contains('color');

D). obj.propertyExists('color');

How do you define a method 'sayHello' in an obj...

A). person.sayHello = function() {};

B). person.sayHello: function() {};

C). person.sayHello = () {};

D). person.sayHello = function {};

What is the purpose of the 'this' keyword in a co...

A). It refers to the new object bei...

B). It refers to the global object.

C). It refers to the current object.

D). It refers to the parent object.

What is the output of console.log(obj.prop) if ob...

A). It prints undefined.

B). It throws an error.

C). It prints null.

D). It prints true.

How do you define a constructor function for crea...

A). function Car(make, model) { thi...

B). Car(make, model) { this.make = m...

C). var Car = function(make, model) ...

D). Car = function(make, model) { t...

How do you get the number of properties in an obj...

A). Object.keys(book).length

B). book.countProperties()

C). book.totalProperties()

D). book.length()

How do you access nested properties in an object?

A). obj.property.nestedProp (B21)

B). obj['property']['nestedProp'] (C21)

C). obj.property['nestedProp'] (D21)

D). obj['property'].nestedProp (E21)