Node.js Tutorials - 44 - Timer Queue

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Timer Queue

[Matt-yzsg]

I just wanted to drop a comment in here to let you know your explanation of the even loop in the last few videos have been extremely digestible. I feel as though I have learned a great deal. Thanks a bunch !

[just_a_living_being]

I really appreciate your efforts and the way you are teaching is awesome 👍

[nandakumart]

Sir, in video 42, you mentioned that all callbacks in the timer queue are executed first, followed by a check for the micro task queue. Nevertheless, with the help of this example, I grasped the exact point. As a continuation of this playlist, I believe it is not a significant issue

[AroFranklin-zl]

In the eg-1, We have Promise as well as next tick. We knows that, next tick has higher priortiy than promises. Second next tick callback create any next tick cb. Then, before execute the 3rd promise CB. The next tick created by second Promise should run right. Or Microtask queue execution is something diff from other other queues.

[vaibhav]

Superb content really enjoyed each and every video till now, keep posting really appreciate it.

[mohamedibrahimmostafa]

in the Microtask tutorial you said that all callbacks within the timer queue are executed which means that the setTimeout 3 should been executed before the nextTick

[onrightside]

Just superb. Learnt a lot from your videos. I'm just waiting for in depth (Latest) Nest course.

[DrClean]

You mention that the setTimeout queue is actually a min heap vs a queue. Is that the case for the other queues or only for setTimer?

[THEBEST-lhpq]

One question. What happens with promises returned by I/O operations? Do they get in promise microtask queue or I/O queue?

[WinchesterD]

Great explanation with visualization, thank you for your videos.

[PM-rste]

Not sure for what use case I am asking this but is it possible to override the hierarchy for processing callbacks?

[CeezGeez]

4:27 when promise #2 adds the nextTick callback while the 3rd promise callback is still in the queue, why doesn't the nextTick callback take precedence there?

[mashrd]

thanks for this tutorial, after this please do express.js tutorial.

[agxxyz]

How are callbacks like setTimeout handled in Node.js? Do they initially go to the call stack or are they saved in memory before being executed by the timer module? you showed these go initally to stack then moved to queue

[guruprasadp]

How setTimeout is being used in node js, since it is part of WEB APIs ?

[trungnguyentrinhquang]

You said that the "timer queue" is actually a min heap, not a queue. So why do they implement it by heap, instead of queue? What is the benefit in this case?

[mazharimam]

But with the promises and nextTick you mentioned that our control was still in promise queue then after nextTick console was printed but here nextTick queue is given preference when it's callback was present in setTimeout . So confusing man.😅

[Wakkyguy]

Also, please explain setTimeout with zero delay vs setImmediate

[ytrnn]

If I put 500, 1000 and zero in the last experiment, display 2, 3, 1 -- don´t do FIFO order.. What I missed?

[trungphamvan]

In the previous video, if I move the Promise before the nextTick, the nextTick will not run before the Promise. Can someone explain why?

Promise.resolve().then(() => {
console.log(`this is Promise.resolve 1`);
});
Promise.resolve().then(() => {
console.log(`this is Promise.resolve 2`);
process.nextTick(() => {
console.log(`this is Promise.resolve in process.nextTick`);
});
});

Promise.resolve().then(() => {
console.log(`this is Promise.resolve3`);
});

process.nextTick(() => {
console.log(`this is process.nextTick 1`);
});
process.nextTick(() => {
console.log(`this is process.nextTick 2`);
process.nextTick(() => {
console.log(`this is process.nextTick in process.nextTick`);
});
});

process.nextTick(() => {
console.log(`this is process.nextTick3`);
});

// Result
/**
* this is Promise.resolve 1
* this is Promise.resolve 2
* this is Promise.resolve3
* this is process.nextTick 1
* this is process.nextTick 2
* this is process.nextTick3
* this is Promise.resolve in process.nextTick
* this is process.nextTick in process.nextTick

*/