Exercise (Video): Basics of Node.js and NPM

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Now that you have Node.js on your computer,

you're obviously wanting to immediately start using it.

So, in this exercise, we will start using Node.

We will set up a packaged, or adjacent, file for

our Git test folder that we have been working with so far.

Then, we will setup a node module called as lite server that

will serve up the contents of our get test folder.

And then we can browse this index.html file and

other files in a browser.

And we will also see how the lite server will enable us to

automatically see updates to our browser window as we make changes to our

index.html file, or any other files in our get test folder.

The lite server is something that we're going to extensively use in this and

future courses, to be able to see the changes in real time

in a browser window as you edit the files of your project.

As I mentioned, we want to set up the package.json file.

So what exactly is this package.json file that we're going to setup?

So here, I have some information from

the npmjs.org site

which specifies what exactly is the role of the package.json file.

So the package.json file serves as the documentation on what all

other packages that your project is dependent upon.

So, for example, when you set up the lite server of your project,

that will be recorded in the package.json file.

And so that, subsequently, you can also make use of that package in the future.

Also, it allows you to specify which specific version of a package

that your project is dependent on.

So even if the package that you depend on changes in the future,

you may insist that you want the user to install only a specific

version of the package for use within your node application.

And also, it makes your builds reproducible,

which means that when you share your code with others,

then they can also do installation of all the node modules,

as we will see later in this exercise, on their own computer.

So obviously your next question will be, how do we create this package.json file?

If you are starting a new project where you want to initialize the package.json

file, then simply type npm init at the prompt in the project folder.

And then that will take you through a set of steps which will enable you to

configure your package.json file.

So let's proceed with that for our Git test project.

So here I am in the git-test folder in my terminal window.

Make sure that you also open a terminal window or a command window and

then go to the git-test folder.

And at the prompt, type npm init.

And then follow along the questions that are asked.

So for the name of the project, we'll just leave it as the default, git-test.

For version, we'll just leave it as 1.0.0.

We can edit that later.

For description,

this is a test directory

to learn Git and Node.

It doesn't matter, type some description there.

And then the entry point, I would just say index.html.

Usually if it is a node package, the entry point will be index.js.

Now this folder that we have setup is

an index.html based folder, so that's why I just typed in index.html.

Test command, nothing.

Git repository, if we had already setup the git repository in the previous

exercise, it'll automatically prompt that for you, if not,

this would be empty and give you an option to type in the git repository URL,

in case you're using an online git repository.

Some keywords for your project, which I'm going to leave blank.

Author, type your name.

Let's be narcissistic.

And the license.

And then, it'll show you the configuration of the package.json file in JSON format.

So if your family have a JSON, does it look very, very familiar to you.

So if this looks all good, let's just say OK and

then that results in the creation of the package.json file.

So now if you list the folder contents,

you would see the package.json file in the folder contents.

Open that Git test folder in your favorite editor,

and then take a look at the contents of package.json file in your editor.

As the next step, we will learn how we can install a node module

using NPM, the Node Package Manager.

So, we're going to install this node module called as light server.

The light server will serve up the contents of this git-test folder in

a server that it starts up so that you can view the contents in a browser.

Given that we have an index.html file,

if we serve up this folder, then it'll be a website.

And you can view the index.html in a browser.

So, let's set up the light server and then we will see how we can make

use of the light server to serve up the contents of this folder.

This is very, very useful because if you're working on a web development

project, you want to see where live version of your web development project.

So that, as you make changes to your project,

you can see the changes immediately reflected in the browser.

So this is a very good node package that is very useful for this purpose.

So let's set up this light server.

To do that, add the prompt.

Type in NPM install.

So notice, if you want NPM to install a node package,

this is how you're going to invoke it and then you'd say lite-server.

And then, we also want to save the fact that our project is using the lite server.

So we will save this information in the package.json file.

So to do that, you're going to type in -- save-dev.

Now the save-dev option specifies that this lite server is used for

development dependency for our project.

If you are installing a node module on which your project is directly dependent

on, then you would install it by simply saying --save option.

So, let's go ahead and install it.

And you wait patiently for the installation to take place.

It'll take all of a few minutes for that to complete its installation.

Once that is installed, then you would immediately

notice when you look at the contents of your folder,

you will immediately notice that there is a folder there created named node_modules.

Now, if you go into the node_module, you will see a whole bunch

of other subfolders in there, which contain node modules,

which are necessary for the likes of our node module and so on.

So let's take a quick tour of the node modules folder to see

what the contents of these are.

Going to my git-test folder, if you're going to the node modules folder,

you would see, as I said, a whole bunch of subfolders there.

Normally you don't need to be venturing into the node modules folder.

They just exist there because they are needed for the [INAUDIBLE].

So as you browse through, you should notice a folder named lite-server here.

When you go into the lite-server folder,

note in particular the presence of the index.js file and

then your package.json file and several other things.

So this contents of the folder comprises the lite-server node module.

But this lite-server node module is dependent on other node modules

to provide it with some additional functionality.

So that's the reason when you install the light server node module, it'll in turn

install many other node modules, on which the light server itself is dependent on.

So that's the reason why you see that explosion of

this folders inside the node modules.

Don't be too concerned about it, the sum total of folders will not be

more than a few tens of megabytes.

So it is not going to fill up your directory with junk.

This is all essential for node to be able to help you.

In case you're curious about the lite-server and how it works and so on,

you can always go down to this GitHub site where the lite-server is hosted.

And then look up the documentation for lite-server.

I will introduce you to whatever you need to know about lite-server as we go through

this course and the remaining courses.

So you don't need to worry too much about it, but just in case you're curious,

you can always go to the site to find out more details about lite-server.

The link is provided in your exercise instructions and

additional resources are part of this lesson.

Once you have completed that, then head over to the.

Editor where you have the folder, Git-Test folder, opened and

then view the contents of the package.json file.

So you would see that the package.json file contains exactly the information that

you configured with your NPM.

So you would see the name version and repository author and

in particular, note this information here.

It says devDependencies, so then it specifies the lite-sever,

and also notice it says hat 2.2.2.

So which means that this particular project depends

upon lite-server that is a at least version 2.2.2 or higher.

So this is very useful for us.

Now why do we need this information here?

Later on, when you go to the other exercises,

you will notice that when you store this on an online repository,

you don't want to be storing everything in your node modules folder.

You will only be storing information of all the files that we have created.

The node modules folder can always be recreated by

typing NPM install at our command prompt.

And then based upon the dev dependencies and

dependencies that are listed in the packager file, all the node

modules that your project depends on will automatically be installed.

We will see that later on how to use

NPM install in this course.

Now that we are at package.json file let's make a couple of edits so

that we will be able to make use of the lite-server to serve up that content.

So right here, in this option called scripts,

let's add in one more here.

So we will say "start".

So start is a command that NPM supports which enables

you to specify a bunch of things that will be started.

So later on we will see how we make use of this.

So here I'm going to say "npm run lite".

And after that test, I'm going to add

in one more entry called "lite",

which I will configure as "lite-server", okay?

With these changes, let's save the package.json file.

And then, now our project is configured, so that now if you start the lite- server,

the contents of your folder will be now served up in your favorite browser.

Heading back to our command prompt, add the prompt.

If I type, npm start, now you see why I put that

entry card start into my package.JSON file.

If I say npm start, whatever the start is configured as in the package.JSON file,

we specify that npm run light, and the lite was specified as lite server.

So essentially, we are saying Start the lite-server.

So, once I type npm start, it will start the lite-server, and

it will serve up the contents of this folder.

Now how do you access the contents of this folder?

If you want to accesses this locally,

you will access it by specifying the you are as localhost:3000.

These are the default settings for the lite-server.

Furthermore, this should automatically open

the browser window of your default browser, and

show the contents of index or HTML in the browser window.

Here you can see that I have opened my editor and

my browser window directed at localhost:3000

simultaneously side by side, so that we can see

how the browser window will immediately reflect

any changes that we make to our Git test folder.

So let me go to index.html.

And then for the sake of space, I'm going to turn that over.

And then, so here, you can see that this is the contents of this.

And then, now, let me add in one more paragraph.

And save the changes, and then you will immediately notice that

the change that I made to my index.html file is reflected into my browser.

This provides a very nice way of being able to observe in real

time the changes that you make to your code being reflected into your browser.

So when you are working on a project, it'll be very appropriate for

you to be able to see the changes immediately.

So when you make a change and then save the file,

the modified code is immediately loaded into your browser.

So you can immediately see the change being reflected in your browser window.

This is a very useful tool while you are doing development of your project.

That is the reason why I introduced you to that lite-server, and

set it up so that we can make use of it, as we develop the website in this course.

If you recall, we had already set up our git-test folder to be a Git repository.

So Checking again, We

will see that we already have three commits in our Git repository.

And this Git repository is already mirrored to our online Git repository

which we have set up in the previous exercise either at Bitbucket or GitHub.

My git-test folder is synced to my

Bitbucket repository in this particular exercise.

So what I'm going to do now is to show you how you can exclude some

folders from your project folder,

and then make sure that they are not synchronized to your online repository.

Now as I said, the node_modules folder can always be recreated

by typing npm install at the prompt.

So that's why when you upload

the contents of your folder to an online Git repository,

or when you do a commit of the folder to your Git repository,

you don't want the node_modules folder or all the subfolders under it to be

included in the commit.

So how do we exclude some folders or

some files from our folder from being checked in into our Git repository?

So to do that, we will set up a file named .gitignore.

So that's the name of the file, .gitignore.

So to create this .gitignore file, we will go to our editor.

So in the editor, in the git-test folder,

I'm going to create a new file and I will name it .gitignore.

Note that the name begins with a dot and

then, the rest of the name is g-i-t-i-g-n-o-r-e.

So this is very very important that you set up the file with exactly that name,

.gitignore.

So let's create this file called .gitignore, and

the first line of that file, we will type as node_modules.

So what this means is that the node_modules folder is going to be

excluded from our git commit.

So once I create that .gitignore file and

then add node_modules into the .gitignore file, let's save the changes.

And then we will now do a commit of the current state of our project

into our Git repository.

I hope you remember your git commands.

Let's do a git status, and then when you do that,

you will immediately notice that you have the index.html

file marked as modified, and then the two new files, .gitignore and package.json.

So, we do a git add ., and then do a git status.

And then you see that all this new files have been checked in into your commit.

Let's do a git commit. git commit -m "fourth commit".

And the files are committed.

Let's push the new commit to our online repository.

So, to do that git push -u

origin master and wait for

it to be pushed to our server.

Now, if you go to your online Git repository,

you will see that the package.json file and

.gitignore would have been checked in into your Git repository.

Going to my Bitbucket repository from the Git test, you will see that

when I look at the source, you will see that the package.json file has been added.

The .gitignore has been added and the new index.html file has been checked in.

So that completes this exercise.

So in this exercise,

we have learned how to set up a package.json file using npm init.

We have learned how to install an npm module.

And we have learned how to use the lite-server npm module to serve up

the contents of our project folder so that it can be viewed in a browser.

So, this is a nice way of serving up your web contents,

your web application or your website, so

that you can see changes in real time being reflected to your browser window.

And then we also saw how we can setup the .gitignore so that some

folders can be excluded from being checked into our Git repository.

This completes this exercise.

So with this, I'm sure you have gotten a good handle on

the use of both Git, and then also node and node modules.

Don't worry, we will be using node extensively, in various ways,

as you go through the courses of this specialization.

This is just a start.

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