Node.js Core Modules & Event Loop 4

Question 1

Which `crypto` module function creates a Hash object used for computing cryptographic digests?

Accepted Answer

crypto.createHash()

Answer

`crypto.createHash(algorithm)` returns a Hash instance; you call `.update()` with data and `.digest()` to get the result.

Question 2

What does `util.promisify()` do?

Accepted Answer

Wraps a callback-style function to return a Promise

Answer

`util.promisify()` takes a function following the Node.js error-first callback convention and returns a Promise-returning version.

Question 3

What is a 'starvation' risk when using `process.nextTick()` recursively?

Accepted Answer

It can prevent the event loop from ever reaching the I/O poll phase

Answer

Recursive `process.nextTick()` calls keep adding to the nextTick queue, potentially preventing the event loop from advancing to process I/O or timers.

Question 4

In Node.js, what is `__dirname`?

Accepted Answer

The absolute path of the directory containing the currently executing file

Answer

`__dirname` is a module-scoped variable that holds the absolute path of the directory where the current module file resides.

Question 5

Which method of the `net` module creates a TCP server?

Accepted Answer

net.createServer()

Answer

`net.createServer([options][, connectionListener])` creates a new TCP server and optionally attaches a connection event listener.

Node.js Practice Test

Node.js Practice Test

Node.js Core Modules & Event Loop 4