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Doing all of this data parsing and response generation code on our own is quite cumbersome and hard

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to scale,

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this already is quite unreadable here

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and of course we could optimized this in certain ways but it's certainly not how you would want to build

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bigger applications. Now similar issues exist on client side Javascript though, there

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also if you have very complex apps with a lot of access to your documents, where you create elements

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and insert elements, this can get cumbersome. Therefore there

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we also learned about React.js or other frameworks that help us with that and we also learned that

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there are in general libraries that can make certain tasks easier,

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the same exists for Node.js.

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You can google for Express.js to find one of the most popular Node.js libraries you can use,

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you can visit its page, expressjs.com to learn more about it and in the end this is just a framework

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for Node.js which makes building web applications, web servers with Node.js easier.

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We install it with npm and in order to do that, we first of all need to turn this into an npm project here,

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so we can do that by running npm init here, npm is available since we installed Node.js and you

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can just confirm all the defaults here.

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Once you did that, you have a package.json file and now you can install new dependencies in this

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project,

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it's the same approach and idea as we had it on the client side when we managed our project there and

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enriched it by npm packages.

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The only difference is that now we will not need webpack or any other tool to use that because Node.js

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natively support these packages in Node modules which is also why the folder is called Node modules as

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you will see and we don't need webpack or anything like that to combine all these files.

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That's one difference, we need it on the client side,

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we don't need it on the server side. So let's now install Express.js with npm install express 

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--save which will install it as a production dependency and you see this new dependency entry

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here in package.json and you see the node modules folder

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and as I said, Node.js is natively capable of working with node modules, you don't need any extra tools

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to combine all these different files. With that, I will rename the file here to pure Node.js and add

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a new empty app.js file where we now can get started with Express.js and learn how we set up a

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web server with that and how that makes it much easier to work with incoming data and also to send back

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responses, how to outsource our HTML code into separate files and not have it inline here and

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how we can then build web applications with that.