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Inside of our case, we now need to take a look at that incoming air, figure out exactly what went

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wrong, and then print out some appropriate air message to the user.

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So I'm going to show you a very quick example of how you might do this, but I'll leave it up to you

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if you want to go through here and kind of put together some more exhaustive cases around handling this

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error.

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In other words, right now, we know for a hundred percent that one possible error is a port already

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being in use.

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So we'll add in some code to handle that case.

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But there might be other kinds of errors that we just don't really know exist just yet.

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And so I'm going to allow you to kind of figure out what those other kinds of errors might be.

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So we'll put in just a very simple approach here, we'll say if your code is.

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E atter in use, then let's go ahead and print up some appropriate air message to our user, then maybe

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we'll do a console air of something like or is in use.

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Try running on a different port.

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And then going to delete the other console log.

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And actually, let's bring that back.

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And we'll just put in an else case, so like I said, we're only going to handle the one Distin situation

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right now.

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So if a port is in use, that's great, we'll tell you exactly what's going on.

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Otherwise, if it's any other kind of area, we're going to tell them, hey, something went wrong.

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We don't really know what figure out what's going on yourself.

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Not great.

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But again, I'm going to leave it up to you to kind of fix that up.

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Now, the last thing we might want to do here, and this is kind of optional, kind of comes down to

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some other topics are going to discuss a little bit later on around Seelie design.

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But what we might also want to do inside of here is force an exit of our program is essentially we just

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failed to start up our server and that was the entire point of running the server command.

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So if we fail to start up our server, then we probably want to say, you know what, there's no point

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in running our program anymore and we just want to forcibly exit.

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So we might do a process, not exit one.

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So this is going to forcibly exit our program with a status code of one, which pretty much just indicates

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that we are exiting with an unsuccessful run of our program.

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Let's say this again, back over a quick test.

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I'll do another note, indexer, and now we're told there is a news.

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Try running on a different port.

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Very good.

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And we get kicked back directly to our terminal.

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The last thing we might do here to kind of enhance the user experience would be maybe tell the user

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how to run on a different port because we're sure not telling them that right now.

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So we might tell them to try to use the P command to run on a different port manually.

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So it might say try to run on a different port.

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And when you do add in, dash up on some other port, maybe in this case four thousand six.

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And if we do that, then everything is going to run successfully.

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OK, so this looks pretty good.

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We've now got some reasonable error handling inside of here.

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The very last thing I would like to do is if we do start up our search process successfully and we know

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if we start listening for actual traffic, we should probably tell the user that, well, everything

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is running successfully and how to now interact with our application.

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You might notice that right now, if we put in that custom port and we start the server, there's no

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message printed to the user whatsoever.

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And so they might be really confused about what they're supposed to do right now.

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So to handle that right after calling serve right here, we might decide to just put in a very quick

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console log.

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With a template string, notice the tactics and we could put in something like opened file name, that's

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the name of the file that we just opened and we are reading cells from and maybe navigate to http localhost

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ohlin.

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And then port.

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To edit the file.

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So essentially just some directions that they need to open up their browser, go to that address if

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they want to see that interface and start interacting with that list of cells, one little fix I need

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to put inside of your is it needs to be option Stockport, not just port.

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Now, if we save this and run it one last time, now we're giving the user some very clear instructions

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so they could very easily copy that, take it over to the browser, see our react application appear

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and start working round with that list of cells.

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OK, so this looks pretty good, I think that we are pretty much all done with our Seelie, we've got

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some pretty reasonable logic inside of here.

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So we're going to take a pause right here, as usual, and back to the next video and continue work

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on our local API.