• University of Saskatchewan

  CMPT 353

CMPT 353 Final Practice Exam – Full

Answer Key

· Q: What is a callback function?

1. A: A function passed to another function to be called later, often used in asynchronous

programming.

· Q: Difference between timeout and interval?

2. A: `setTimeout` runs a function once after a delay; `setInterval` runs it repeatedly every

delay interval.

· Q: What is a promise?

3. A: A Promise is an object representing the eventual completion or failure of an

asynchronous operation.

· Q: What are the 3 states of promises?

4. A: Pending, Fulfilled, Rejected.

· Q: What order is Node simple event loop?

5. A: Call Stack → Microtasks → Callback Queue (Macrotasks).

· Q: True/False: NodeJS gives priority to the call stack before the message/job queue?

6. A: True.

· Q: List all phases of the NodeJS event loop.

7. A: 1. Timers, 2. Pending Callbacks, 3. Idle/Prepare, 4. Poll, 5. Check, 6. Close Callbacks.

· Q: What is the syntax of async functions?

8. A: `async function name() {}` — allows use of `await` inside the function.

· Q: How are async functions related to promises?

9. A: Async functions always return a promise. `await` pauses execution until the promise

resolves.

· Q: Relational model matching terms:

10. A: Table = Relation, Row = Tuple, Column = Attribute, Column Set = Degree, Row Set =

Cardinality, Identifier = Key, Legal values = Domain.

· Q: What is a primary key?

11. A: A field that uniquely identifies each row in a table.

· Q: What is a foreign key?

12. A: A field that references the primary key of another table.

· Q: What are ACID properties?

13. A: Atomicity, Consistency, Isolation, Durability — ensure reliable transactions in

databases.