JavaScript Property Descriptors, Accessors, and Object Integrity Quiz

Review

1. What does Object.getOwnPropertyDescriptor(obj, "x") return?

   It reports the descriptor of the specified own property.
2. Which fields belong to a data descriptor?

   Data descriptors use value and writable; accessor descriptors use get and set.
3. For a newly created property defined with only { value: 1 }, what is writable?

   Omitted attributes on a newly created descriptor receive their specified default values, including writable: false.
4. What does enumerable: false affect?

   Enumerability controls enumeration, not existence or direct access.
5. What does configurable: false primarily restrict?

   Non-configurable properties have strong restrictions on later structural changes.
6. When is an accessor getter normally invoked?

   A property read invokes its getter.
7. What does the right-hand side of an accessor assignment become?

   The assigned value is passed to the setter.
8. What does Object.seal do?

   Sealing prevents adding own properties and makes existing own properties non-configurable.
9. What important limitation does Object.freeze have?

   Nested objects are not frozen automatically.
10. What happens in strict mode when assigning a different value to a non-writable property?

    Strict-mode failed writes to non-writable properties throw TypeError.