Sequential vs parallel async execution in Node.js - Quick Revision & Key Differences

Recall & Review

beginner

What does sequential async execution mean in Node.js?

Sequential async execution means running asynchronous tasks one after another, waiting for each to finish before starting the next.

beginner

What is parallel async execution?

Parallel async execution means starting multiple asynchronous tasks at the same time and waiting for all to finish together.

beginner

Which Node.js function helps run async tasks in parallel and wait for all to complete?

Promise.all() runs multiple promises in parallel and waits for all of them to resolve or any to reject.

intermediate

Why might you choose sequential async execution over parallel?

You choose sequential execution when tasks depend on each other or when you want to limit resource use to avoid overload.

beginner

What is a downside of running async tasks sequentially?

Sequential execution can be slower because each task waits for the previous one to finish before starting.

Which method runs async tasks in parallel in Node.js?

A Promise.all()

B setTimeout()

C async function() {}

D console.log()

Promise.all() runs multiple promises at the same time and waits for all to finish.

What happens in sequential async execution?

A Tasks run randomly

B Tasks run all at once without waiting

C Tasks run one after another, waiting for each to finish

D Tasks run only if previous failed

Sequential means tasks wait for the previous to finish before starting.

Which is a benefit of parallel async execution?

A Faster overall completion

B Uses less memory

C Runs tasks one by one

D Avoids all errors

Running tasks in parallel can finish faster since they happen at the same time.

When should you prefer sequential async execution?

A When you want to run tasks randomly

B When you want fastest speed

C When tasks are independent

D When tasks depend on each other

Sequential is best when one task needs the result of the previous.

What does Promise.all() return?

A An array of functions

B A promise that resolves when all input promises resolve

C A single value immediately

D A callback function

Promise.all() returns a promise that resolves with all results once all promises finish.

Explain the difference between sequential and parallel async execution in Node.js.

Think about waiting times and task order.

When would you choose sequential async execution over parallel, and why?

Consider task dependencies and resource limits.