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
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 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 change the properties of a constant object in JavaScript?
A). A. Use Object.freeze()
B). B. Use const for each property
C). C. Use the delete keyword to remove properties
D). D. Use dot notation or bracket notation
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
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
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 data type of a constant object in JavaScript?
A). A. Object
B). B. Array
C). C. Function
D). D. String
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