How do you add a new property 'age' with value 25...
A). person.age = 25;
B). person['age'] = 25;
C). person.add('age', 25);
D). person.push('age', 25);
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)
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');
What happens if you access a non-existent property...
A). It returns undefined.
B). It throws an error.
C). It returns null.
D). It returns true.
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');
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.
What does Object.keys(obj) 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.
What is the purpose of the 'super' keyword in a ...
A). It calls methods from the paren...
B). It creates a new instance of the...
C). It refers to the current object.
D). It checks for property existence.
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()