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The publisher is all put together so let's now work on implementation for our listener.

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The goal of our listener.

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We're going to come up with a subject name or the channel that we want to listen to.

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We're gonna pass that into the stand client to create a subscription and then we're going to watch this

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subscription or anytime it receives some data to back inside of my listener T.S. file.

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At the very top we're going to import Nats once again from node that streaming will then create my clients

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which remember we referred to Muni convention as simply Stan so that's dot connect to once again put

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in some kind of mysterious looking arguments right here.

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Just bear with me for a moment we will come back to the Connect function.

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It's going to put in ticketing.

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I'm going to put in one two three and then an object and inside there will be a your l and very similar

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to what we had last time we'll put an H TTP local host or at 4 2 2 2

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0 then watch for a Connect event

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so after we have successfully connected once again let's just do a quick console log and say hey our

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listener connected to Nats I'll do a console log of listener connected to Nats let's now go over to

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our terminal and just tried to run this program and make sure that the listener can connect as well.

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So back at my terminal I'm going to find a window where I was running the publisher.

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If you are running a terminal where you can do a split screen I highly recommend you tried to pull up

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a split screen right now.

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So for me I'm making use of item two on Mac OS a hotkey to do that is command D so I can hit command

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D.

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And now I get the split screen right here so this will allow us to watch events being published and

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listen for at the same time.

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If you do not have a terminal where you can do a split screen no problem just open up a second terminal

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window and maybe drag them next to each other just like this.

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You can see the events being published and listened to at the same time then inside this second window.

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I'm still inside of my Nats dash test directory and inside there I will run NPM run listener to me NPM

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run listen we gave it a slightly different script name so NPM run listen and it looks like all right.

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We were able to connect to Nats at this point.

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We've got a lot of extra information inside of here so this restart stuff typescript log in information

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and so on.

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So really quickly I can go back to both these scripts and right after the import statements I'm going

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to add in a console dot clear I'm gonna put them inside of listener and I'm going to put it inside of

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the publisher as well.

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Right after the import statement now whenever this stuff runs or whenever our code gets reran because

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we change the file now we'll just see the console logs at the very top and just remove a lot of the

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garbage that was in here previously one other thing I wanna mention very quickly and this is gonna become

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very relevant as we're gonna want to start to publish a lot of events here in just a moment.

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If we ever want to restart our program while we are using T.S. no Dev we can select the terminal window

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that's running our program type in the letters R S and then hit enter and that will automatically restart

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our program.

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So right now every single time I type in RSS and then hit enter I am restarting my program which means

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I'd create a new connection to the Net server and then I publish a brand new event.

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So if I do this a couple more times I've now probably published like five six or seven different events

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on that particular channel the channel with the subject of ticket colon created OK.

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So let's now go back over and work on our listener implementation inside of listener.

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Yes.

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After we successfully connect we're going to come up with the name of the subject that we want to listen

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to and use it to create a subscription so I'm going to write right after the council log on to subscription

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is Stan dot subscribe and we're gonna put in our subject right here which is ticket colon created then

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after creating the subscription.

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Remember this is the object that we're going to listen to and we're going to receive some data through

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the subscription contrary to how many other libraries work where you might be used to adding in a callback

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function like that that would be invoked with whatever data we receive not how it works with no dates

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dreaming.

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Instead we create the subscription first and then listen to a very particular type of event off the

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subscription itself.

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We're going to call subscription dot on message so as I mentioned at the end of last video in the world

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of Nats they don't really refer to these events being exchanged as events.

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Instead they referred to as messages you'll see this message.

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Terminology floating around a little bit then the argument to this is going to be the actual message

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which we frequently abbreviate as simply NSG.

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It must be right here is not just the raw data.

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Instead it's got a couple of different properties inside of it.

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We'll take a look at over time so right now let's just do a console log of.

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Message received so we're not actually looking at that message.

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We're not actually trying to inspect any of the data inside it just yet.

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I just want to make sure that we can actually receive a message that's all OK.

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I'm going to save this.

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I can make sure both files are saved.

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And then I'll go back over to my terminal.

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Now in theory our listener is creating a subscription and listening to that very specific channel.

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So let's now go back over to our publisher.

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We're going to restart the publisher and attempt to publish another event.

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The instant we do so and I really do mean the very instant we do so we should see a console log from

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the listener saying that it received a message.

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So let's try this out on the publisher.

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I'm gonna put an R S hit enter and there we go.

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We have received that message.

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OK.

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So that's a very basic chain of publishing some data and receiving some data as well now.

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Everything at this point really seems pretty simple and straightforward.

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Right.

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It's pretty much a basic eventing setup.

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Nothing too crazy.

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You might you think at this point that I'm going really slowly and he might be screaming at the screen

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saying Steven can you like hurry it up and get to the point well believe you me we were going slow for

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a reason it's really important for you to understand these very basic concepts because in the coming

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videos we are going to absolutely blow the lid on complexity here.

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We are really going to start to plumb the depths of gnats and really understand what is going on behind

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the scenes because as you will see very very quickly some very small settings inside of here is going

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to dramatically change how our application works.

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So I'm really excited for the coming videos.

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So quick browser here and we'll continue in just a moment.