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
How can you ensure that a constant object remains unchanged in JavaScript?
A). A. Use Object.preventExtensions()
B). B. Use Object.freeze() to freeze the object
C). C. Use const for each property
D). D. All of the above
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 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
Which statement about constant objects in JavaScript is correct?
A). A. Constant objects can have their properties reassigned
B). B. Constant objects cannot have properties added or removed
C). C. Constant objects are only applicable to primitive values
D). D. Constant objects are mutable
What is the data type of a constant object in JavaScript?
A). A. Object
B). B. Array
C). C. Function
D). D. String
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
How can you prevent modifications to the properties of a JavaScript object?
A). A. Use Object.preventExtensions()
B). B. Use const for each property
C). C. Use Object.freeze() to freeze 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