How can you delete the age property from the person object?
A). delete person.age;
B). remove person.age;
C). person.age = null;
D). person.age.delete;
What is the output of console.log(person.greet()); if var person = {greet: function() {return 'Hello';}};?
A). Hello
B). Undefined
C). Error
D). Hello
How can you check if the age property exists in the person object?
A). 'age' in person
B). person.has('age')
C). person.contains('age')
D). person.hasOwnProperty('age')
How do you add a new property gender with value male to the person object?
A). person.gender = 'male';
B). person.gender = male;
C). person.gender = ['male'];
D). person[gender] = 'male';
What is the correct way to create an object in JavaScript?
A). var obj = {};
B). var obj = [];
C). var obj = ();
D). var obj = <>;
How do you define a method inside a class in JavaScript ES6?
A). methodName() {}
B). this.methodName = function() {}
C). function methodName() {}
D). methodName: function() {}
What does Object.keys(person) return if var person = {name: 'John', age: 30};?
A). ['name', 'age']
B). ['John', 30]
C). {'name', 'age'}
D). {'John', 30}
How do you iterate over all properties of an object var person = {name: 'John', age: 30};?
A). for (var key in person)
B). for (var key of person)
C). forEach(key in person)
D). forEach(key of person)
What is the purpose of the this keyword in a constructor function?
A). It refers to the new object being created.
B). It refers to the global object.
C). It refers to the current object.
D). It refers to the parent object.
How do you call a method from a parent class in a subclass in JavaScript ES6?
A). super.methodName()
B). this.methodName()
C). parent.methodName()
D). base.methodName()