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 inherit properties and methods from a...
A). class SubClass extends SuperClas...
B). class SubClass inherits SuperCla...
C). class SubClass implements Super...
D). class SubClass derives SuperCla...
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 is the correct way to create an empty object...
A). var obj = {};
B). var obj = ();
C). var obj = [];
D). var obj = <{}>;
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 a property called 'name' from an...
A). person.name
B). person['name']
C). person->name
D). person::name
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 create an instance of the 'Car' objec...
A). var myCar = new Car('Toyota', ...
B). var myCar = Car('Toyota', 'Corol...
C). var myCar = create Car('Toyota',...
D). var myCar = construct Car('Toyo...
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 will console.log(obj.toString()) output?
A). The string representation of...
B). The object itself.
C). An error.
D). 1