MEAN Node.js Async Patterns and Performance 5

Question 1

What is the primary advantage of using Node.js Streams over reading an entire file into memory?

Accepted Answer

Streams process data in chunks, reducing memory footprint for large files

Answer

Streams process data piece-by-piece, so even multi-gigabyte files can be handled with minimal memory usage.

Question 2

What is the purpose of `process.nextTick()` versus `setImmediate()` in Node.js?

Accepted Answer

`process.nextTick()` fires before I/O callbacks in the current iteration; `setImmediate()` fires in the check phase of the next iteration

Answer

`process.nextTick()` callbacks run at the end of the current phase before moving to the next event loop phase, while `setImmediate()` runs in the check phase of the following iteration.

Question 3

In Node.js, what does the `--max-old-space-size` flag control?

Accepted Answer

The maximum heap memory allocated to the V8 engine

Answer

`--max-old-space-size=<MB>` sets the maximum heap size for V8's old generation space, preventing out-of-memory crashes for memory-intensive apps.

Question 4

What is a key characteristic of async generators in Node.js?

Accepted Answer

They yield values lazily over time and can be iterated with `for await...of`

Answer

Async generators use `async function*` syntax and `yield` to produce values lazily, which can be consumed with `for await...of` loops.

Question 5

What problem does the `cluster` module solve in Node.js?

Accepted Answer

It allows a Node.js app to spawn child processes that share the same server port, utilizing multiple CPU cores

Answer

The `cluster` module forks the process into multiple workers that share the same listening port, enabling multi-core CPU utilization for Node.js servers.

MEAN - Stack Development Practice Test

MEAN - Stack Development Practice Test

MEAN Node.js Async Patterns and Performance 5