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In this video we're going to get a quick reminder on how we create a listener you might recall that

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inside of our common module and the SRT directory in the events folder we had created that base listener

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class.

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This was an abstract class and so we're going to extend this to build out different classes inside of

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each of our services that are going to listen for very specific events when we extend this listener.

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We're going to make sure we provide a event type as the generic type.

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And then inside of the child class we're also going to be required to define a subject such can be subject

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we want to listen to on that string server a Q Group name and we'll get a reminder on what that's about

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really quickly.

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And then finally the on message function the on message function is what's going to actually receive

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an event that's we're going to implement some amount of business logic.

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The first argument is going to be the data inside the event and the second argument will be a message

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and we'll get a reminder on what that message is in a little bit.

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ASM The other thing I want to remind you about is that when we create an instance of a listener we have

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to provide a Nats client to it when we create an instance of a listener and provide the Nats client

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that doesn't actually start the thing up listening.

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Instead we have to call the listener method which we have defined down here.

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This is what is going to actually tell the client to start to subscribe or create a subscription and

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listen for events on a very particular subject or channel then whenever we receive a message that is

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when we were going to actually call the on message function so in total in order to create a listener

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we're going to create a new file inside of our different services.

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It's going to extend this base listener class we're going to plug in at the event type 1 to listen for

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and then define a couple of different properties inside of it.

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And that's pretty much it.

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Now as a reminder the first listener we're gonna put together is give me a listening for the ticket

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created event and we're going to implement that inside of our order service.

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Let's take a quick pause right here and then start to implement this first listener in the next video.