Name: Bubble Up Your Node.JS I/O - Matteo Collina｜JSConf Hawaii 2019 (Bubble Up Your Node.JS I/O - Matteo Collina | JSConf Hawaii 2019)
Uploaded: 2021-01-14T10:27:27.000Z
Duration: 24 min 29 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

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Add Matic Alina, please ask me questions.

So I'm here today to talk about the No Dario, you might ask why Note?

Well, I am part of the notary s technical steering committee.

If you have questions about North courting me, I'm so Ah, I'm also ah, principal accurate in here for me on a professional service company distributed around the globe, but busy in Ireland.

Also, another little bit of intro There is these lights.

If you have a laptop, there are some interactive visualizations.

So if you have a laptop out and you want to play with them these of these lights you can take a picture, whatever.

Um, when everybody starts with note, they start with a very simple question out of the bag.

You know, you have a socket coming in on http request coming in and you want to react Thio those activity And you know what?

Everybody does well I can use the inspector protocol.

The the bug on application running in production where I have a lot off concurrency in place.

I've done this and this and I've said it.

You could stop a thread single tried in just the bag back.

So most of the stuff is because no Js is based on a concept called the evidence and you're probably are familiar with the No David Loop.

Um, okay, How many if you think they are from either with a no Devon loop.

How many of you have seen this less people?

Okay, that's the most Eden piece off node lower that you can find.

If you want to know more about how note works and this is our no Devon loop works, probably not really easy to understand.

So let's reached one more easy to, uh, understand version because probably a little bit more clear to everybody.

So when JavaScript is exact executes, the only thing that note application does when it leads to a Iot, it talk to the colonel.

I think your barrier or a threat and says When this event happens, when this condition happens, please call back.

When this finishes that the only thing that that no does on dhe it specified a passing as a musket function.

And, you know, some event happens like you are receiving some data from a socket and that it calls back, and then he wants to call that function.

Whoa, there is an event you here and the event you means that all the functions are processed one at a time on.

So just to repeat at the dusky primetime specify effort at the function as a listener to some io event, and then the your event happens and the function is called.

To all of this, we have only one function executing again given time.

And this is one of the key tenants off Annie Know Js and you know, Js function now you might ask why all of this matter why I'm doing a singles activity wouldn't make things simpler.

Yes, and now it makes things simpler to code.

However, that is one key piece that is a little bit obscure, which knowing which code is running relative to one another.

You scheduled a promise if you run a promise if you do next IQ, or if you do set immediate, you know I'm no throwing set time out Vero in there because that's even trickier.

So next week, every police executed before promises are resolved and before any other your events promises are.

If you do new promise, the function is executed.

Sink a lovely, but then resolve our synchronously and before any other io events set immediate.

Instead, exists eyes the full event loop that we told you that we've told you, you know, and have not thrown in city meets a time a Vera because that's another rival complication.

So again, the artist piece off information.

That thing that when a newbie starts working with note, is to know when a chunk of code is executed relative to one another.

So going back to the question out to the bug multiple a synchronous activity.

Because, you know, we have multiple things happening.

How do we have a bad bug on that is happening Only when I'm calling three different routes at the same time and the moon is aligning and Marcie's over there?

And her I don't understand what what is happening in here is very hard.

So it goes back to a problem that something that you're missing in basket, which is the concept off their synchronous context.

So let's look at a bad, very basic, http Server of written in Notre.

And you can see that we do our http, create server and we're passing a function this function.

In fact, when we receive an http request from a browser, you have a new logical sequence context that is being created, which means, you know, this is your transaction.

This is a logical concept that is living in there.

All the things that the sun from this one will be, you know, linked.

One wished another, mainly because they're part off the same closure.

You see, it's a closure created here, so they're part of the same closure.

And then when I create another closure, you know it's in here.

Okay, on dhe, the context is being the response is being propagated just by using that, um so it's really powerful, right?

However, there is no concept off our signals.

So you know it's something that is built in into our treasure works and how the event loop works.

But there is no way to control in any, uh, reflection oriented way this type of things.

So it's completely a logical counts construct, but is not a language, not the language feature.

There is some work in making these a reality where there's actually a concept in the language back and some of the war.

You can find some of the work done by the diagnostics working group in know Js.

Check it out and it goes a little bit into the deep depths of this, and it's really, really interesting to read.

Um, then well, if there's no concept off seniors context.

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Bubble Up Your Node.JS I/O - Matteo Collina｜JSConf Hawaii 2019 (Bubble Up Your Node.JS I/O - Matteo Collina | JSConf Hawaii 2019)

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