Which of the following is a valid way to define a constant object in JavaScript?
A). A. const obj = { a: 1, b: 2 };
B). B. const obj = new Object({ a: 1, b: 2 });
C). C. Both A and B
D). D. None of the above
Which of the following will result in an error when using a constant object in JavaScript?
A). A. Modifying an existing property
B). B. Adding a new property
C). C. Reassigning the object reference
D). D. None, all operations are valid with constant objects
What is the data type of a constant object in JavaScript?
A). A. Object
B). B. Array
C). C. Function
D). D. String
Which statement is true about constant objects in JavaScript?
A). A. The properties of a constant object cannot be changed
B). B. Constant objects are frozen and immutable
C). C. Constant objects cannot have properties added or deleted
D). D. The object reference can be reassigned
What is the result of the expression Object.keys(person).length for the following code snippet?
A). A. 1
B). B. 2
C). C. 3
D). D. Error
What happens if you try to delete a property from a constant object in JavaScript?
A). A. The property is deleted successfully
B). B. A TypeError is thrown
C). C. A SyntaxError is thrown
D). D. Nothing happens
What is the output of the following code snippet?
A). A. { x: 10, y: 20 }
B). B. { x: 20, y: 10 }
C). C. { x: 10 }
D). D. Error
What does the const keyword do when used to declare an object in JavaScript?
A). A. Makes the object immutable
B). B. Prevents reassignment of the object reference
C). C. Freezes all properties of the object
D). D. All of the above
What happens if you use Object.freeze() on a constant object in JavaScript?
A). A. The object reference becomes mutable
B). B. The properties of the object become immutable
C). C. The object becomes frozen and cannot be modified
D). D. A TypeError is thrown
Which of the following will cause an error when used with a constant object in JavaScript?
A). A. Modifying a property using bracket notation
B). B. Adding a property using dot notation
C). C. Deleting a property
D). D. Reassigning the object reference