Node.js Technology & Digital Applications 5

Question 1

What is the output of `console.log(0.1 + 0.2 === 0.3)` in Node.js?

Accepted Answer

false

Answer

Due to IEEE 754 floating-point representation, `0.1 + 0.2` equals `0.30000000000000004`, not exactly `0.3`, so the comparison is `false`.

Question 2

Which npm script name is automatically executed when you run `npm test`?

Accepted Answer

"test"

Answer

`npm test` looks for and runs the `"test"` script defined in the `scripts` section of `package.json`.

Question 3

What does enabling `WAL` (Write-Ahead Logging) mode in SQLite provide when used with a Node.js application?

Accepted Answer

Better concurrent read performance without blocking writes

Answer

WAL mode allows concurrent reads alongside a write without blocking, improving throughput in Node.js apps where reads are frequent.

Question 4

In Node.js, what is the difference between `setImmediate()` and `setTimeout(fn, 0)`?

Accepted Answer

`setImmediate()` fires after I/O events in the current loop; `setTimeout(fn,0)` fires in the timers phase with a minimum ~1ms delay

Answer

`setImmediate()` is designed to run after I/O callbacks in the check phase, while `setTimeout(fn, 0)` runs in the timers phase with a minimum delay, making their order context-dependent.

Question 5

What is the purpose of the `helmet` middleware package in an Express.js application?

Accepted Answer

Setting secure HTTP response headers to protect against common web vulnerabilities

Answer

`helmet` sets HTTP headers like `Content-Security-Policy`, `X-Frame-Options`, and `X-XSS-Protection` to mitigate common attacks.

Node.js Practice Test

Node.js Practice Test

Node.js Technology & Digital Applications 5