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 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
Which statement best describes the behavior of a constant object in JavaScript?
A). A. The object and its properties cannot be changed
B). B. The object reference cannot be reassigned
C). C. All properties are immutable
D). D. The object cannot be modified after declaration
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
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
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 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 check if an object is frozen in JavaScript?
A). A. Using the frozen property
B). B. Using the isFrozen() method
C). C. Using the Object.isFrozen() method
D). D. All of the above
What is the output of the following code snippet?
A). A. { a: 1, b: 2, c: 3 }
B). B. { a: 1, b: 2 }
C). C. { c: 3 }
D). D. Error