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
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 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
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 happens if you try to reassign a constant object to a new object in JavaScript?
A). A. No error, the assignment is successful
B). B. TypeError is thrown
C). C. SyntaxError is thrown
D). D. ReferenceError is thrown
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 happens if you try to modify a property of a frozen object in JavaScript using Object.freeze()?
A). A. The property is modified successfully
B). B. A TypeError is thrown
C). C. The property is deleted
D). D. The object becomes mutable
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 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