JavaScript Assessment Test for Hiring

1. What does this code log? `let x = 1; function test(){ console.log(x); let x = 2; } test();`

• A.1
• B.2
• C.undefined
• D.ReferenceError

2. Which pattern best avoids callback nesting while preserving readable async flow in modern JavaScript?

• A.Deeply nested callbacks
• B.Global mutable flags
• C.Promises with async/await and clear error handling
• D.Synchronous XHR requests

3. A function mutates an array passed into it, and a UI updates unexpectedly elsewhere. What is the core issue?

• A.JavaScript cannot pass arrays to functions
• B.Shared reference mutation can create side effects across the app
• C.Arrays are immutable by default
• D.The DOM automatically clones arrays

4. What does `Promise.all()` do when one promise rejects?

• A.It waits for all promises and ignores the rejection
• B.It resolves with the successful values only
• C.It rejects immediately with that error
• D.It converts the rejection into `null` automatically

5. Why might using `var` inside a loop with asynchronous callbacks produce surprising output?

• A.`var` values are encrypted
• B.`var` is function-scoped, so callbacks may all close over the same final value
• C.`var` forces synchronous execution
• D.`var` cannot be used in loops

6. A candidate can solve syntax questions but consistently chooses dense, unclear code over a slightly longer readable alternative. How should that be scored?

• A.As fully correct with no concern
• B.As a code-quality risk despite technical correctness
• C.As evidence they should automatically be senior
• D.As irrelevant because readability is subjective