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Welcome back.

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So as I promised in the last video we're now going to see how we use them and we're going to install

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a few packages.

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Hopefully it's a fun lesson.

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The two packages that we are going to install are pretty silly and definitely not the most useful.

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But fundamentally we install them the exact same way that will install packages like Express and mongoose

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in the next unit.

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Before we begin the two objectives that I want to make sure to hit are showing you how to use NPM install

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the command and Pimm install to install a package and then also using require to include a package in

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a js file.

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Let's begin first thing I'm going to do is make a new folder make directory and I'm just going to call

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this demo app and going to CD into demo app just like that.

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And I'm going to make a new file here.

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So touch app.

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J.S. and then I'll open that up and I'll just start with a really simple consulate log from J us and

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save and run it node.

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Yes we're doing this just so that we have a place to install our packages in.

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We want to make a directory for them.

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We want to have a file that will run them with.

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So that's why we have this app dodgiest file inside of the demo app directory.

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The first package that we're going to use is something called Catch me.

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You can search for it on NPM if you just search for Cat me.

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It's the first result and the only result.

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Like I said it's a pretty silly package.

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What it does is it makes you ASCII art Katz.

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So things like this or this here or even this gigantic one here.

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But the goal is that it's just one or two javascript methods that you call and they print out a bunch

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of text that someone else went through the effort of figuring out how to print these cuts.

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The very first thing we need to do is install it.

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So it's called Cat dash me.

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So then we just need that name and we go back to our terminal here and we run NPM install cat dash me

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so that command NPM install is really important.

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We'll be doing it constantly every time we started a new application.

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Every unit will be installing five or six different packages so you get used to using that pretty quickly

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before I hit enter.

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I do want to just point out what the demo app currently looks like.

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It's empty except for app dot JS.

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But as soon as I hit NPM install Cat me it will take a moment.

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It's going to NPM servers and finding Cat me and getting the correct files and installing it.

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And now if I hit LS here you'll see we actually have a new folder that wasn't there before.

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Node modules and I'll open it up here.

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There we go node modules and then inside of that we have Cat me and inside of Cat me.

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There's a bunch of files and these are the files of that package.

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So this is the code that someone else wrote.

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You can see these are the different cats that will be printed out.

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So node modules is a directory that is automatically created for us whenever we install a package and

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all future packages that we install.

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So in a moment we'll install a second one.

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We'll also live instead of node modules.

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So then it will look like node modules has caught me and then our other package which tells knock knock

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jokes will be instead of node modules as well.

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So that's how we install a package but to use it we need to import it into our application and to do

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that we use the require command.

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So I'll show you here.

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So that looks like this far something I'll just call it something for now.

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Equals require cat dash me which is the name of the package when I run this code it will automatically

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look for a package called Cat me or a file called Cat me and you will find inside of node modules.

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Cat dash me and it knows which code automatically to include.

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It has to do with this file called index Dot.

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Yes that's a little bit too detailed.

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So it automatically includes all of the right code from here.

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It grabs everything that's needed and then it sticks it inside a variable called something and that

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can be whatever we want it to be called.

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Now I'm going to head back to the docs and show you how we can use catenary.

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This is the other really important part of package's is using the docs finding out how the packages

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work and kept me is very very simple which is why we're using it now.

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But some of the things that we use later on we'll have 100 or 200 different methods and they all work

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slightly differently and you'll have to be very careful about reading the docs to understand the ins

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and outs of some of the functionality but as I said kept me it's very simple.

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All we do is require it which we already have done.

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And in this case they save it to a variable Cat me and then to get a random cat you just run Cat me

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.

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So the name of this variable.

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Then we add parentheses afterwards.

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And that executes a function.

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What that tells us is that when we require kept me what we get back is a function that we can execute

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just like any other function that we've created.

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Just like alert in the browser or consulate log.

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When we add parentheses it will execute it.

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So let's go ahead and try that.

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Now I'll get rid of this.

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But log and let's change the name so it's not something let's just call it cat.

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I want to show you that the name doesn't have to be kept me.

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And then we'll just run cat just like that.

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And it did mention that it returns the ASCII art cat.

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It doesn't printed out.

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So if we just run cat and I run my file now which is node aptest J.S. we don't actually see anything

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.

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The very fact that we didn't get an error when we ran the cat function tells us that our require worked

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.

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But of course we want to see the cats.

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That's what we're here for.

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So I'm just going to cancel that log that so cancel dog cat and save.

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And now I'm going to clear and make some space here just so that you can be impressed that clear command

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is just a nice way to clear out the terminal.

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And now what I want to do is run node apps.

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Yes.

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And we get a random cat and let's do one more.

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There we go.

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Fun stuff.

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We now have two random cats.

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And this is all code that we never wrote.

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We're just using someone else's package.

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Yes it's simple but it's the exact same concepts to use a more serious package like Express which is

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exactly what we have right here.

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Var express equals require express or far mongoose equals require mongoose.

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So we'll be doing this in just a few videos but it's the exact same syntax.

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Var something equals require the name of a package.

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So that was kept me.

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Now I want to show using this other package called Knock knock jokes and all that it does it's also

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very simple.

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We install it first and require it and then we execute it.

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Knock knock is what they need the variable in this case.

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But again it can be called anything.

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And when we execute that function it returns knock knock joke.

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You want to make sure we're in the same directory as the node modules folder.

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We don't want to be outside of this directory like here.

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If I install that right here it would make a another node modules directory here so it wouldn't be installed

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in the same place as the cat in the package.

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So we'll go back into our demo app where we see node modules and we need to run and PM install knock

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knock joke.

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Let's double check knock knock jokes with the S in the end and hit enter.

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It will take a moment.

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It goes and finds it and then you can see if I type LS or I do ls node modules we now have two folders

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inside if they're cat me and knock knock jokes and I'll open that up.

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Let's look at knock knock jokes.

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We have this index that genius.

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And this is the file where the knock knock jokes are.

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It kind of ruins the magic to actually look at it because it will spoil the jokes.

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But we can see that there's a joke Saray where each joke is an object and then down here there's this

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format joke function that will overturn this.

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Knock knock Who's there.

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Joked name joked out name who and so on are definitely ruining the magic though.

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So let's close out of here and let's import the knock knock joke package into our code here so we'll

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just do it up top.

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Most of the time you'll see a lot of import statements at the top rather than being spread out across

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a file.

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They're all at the top.

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Like I have here.

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These are all of the required statements to import packages.

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So we're going to do the same thing.

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Var joke equals require.

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And then the name of the package which is Naach dash knock dash jokes and save.

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And then all we want to do is execute that joke just like that and we'll cancel that log it again because

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it just returned to joke.

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And if you want to see it we need to print it out.

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So now we'll get a cat and a joke if all works well there are two packages have been installed and imported

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correctly.

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So we save and then we'll expand this and we'll run node apps.

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Yes we get our cat and we get this joke.

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Knock knock.

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Who's there.

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ABBE.

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ABBE who.

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Abby birthday to you.

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And one more knock knock who's there.

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She is.

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She is who.

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She's a cute girl.

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She's a cute cat too.

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All right that's enough of that.

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Let's wrap up.

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Now let's review some of the basics here.

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Those two commands I mentioned in the objectives are NPM install.

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So we ran NPM install knock knock jokes and NPM install Cat me whenever we run an install it goes and

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finds that code on NPM and once it downloads that code it saves it to a folder directory called node

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modules which if it doesn't exist yet it will make node modules the first time.

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But then as soon as it does exist it just adds the newer modules into the same node modules directory

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.

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But just downloading them or installing a package doesn't let us use it.

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We still have to include it in our code with the required statement and we require with the name of

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the package.

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Cat dash me or knock knock jokes.

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Save it to a variable and then we can use that variable which is really just storing all of the code

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that's coming back from Cat me and knock knock jokes.

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We can use that variable throughout the rest of our code.

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All right so that's it.

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And the next video I'm going to have you do another quick exercise.

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This one should be pretty fun because you're going to be using another package one that's actually a

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little bit more useful than printing cad or knock knock jokes.

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I won't spoil it yet.

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I'll see you in the next video.