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In this video.

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Let's have a look at the road map for learning.

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Express J is the first concept you need to know is what we call routing, and we will talk about it

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as a Node.js developer.

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We need to know how to implement routing in your application and after that you need to know what is

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middleware.

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Because Xpress is all about middleware and you use middleware for a lot of logic.

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In our application, for example, we use middleware to implement what is called authentication, authorization

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and business logic.

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So when you say authentication, it simply means that allowing a user to enter into our application

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and authorization simply means that after a user has logged in, what kind of action the user can take

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inside our application, that's what we call authorization.

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Again, we have a section for each of these concepts.

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Now, what about the business logic?

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Well, let's take this for example.

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Let's say that we have a block application, and for block application we specify that a user can create

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up to ten posts.

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If you want to create more than ten posts, then you need to pay or subscribe to our payment plan.

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So this is an example of business logic and application.

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Or for example, if a user account is not verified, you need to send a message to the place, verify

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your account before proceed.

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So these are examples of use cases.

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So we use middleware a lot.

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So you dive in more to know what is middleware.

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And after no matter what we are going to talk about is what you call error handling because you are

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going to use the middleware concept to talk about how we can handle errors in our application.

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So after knowing this, the next one is called template engine.

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How we can pass dynamic data into a HTML.

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Now that we know the Roadmap for learning experience in video, let's look at what is import and export

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because we are going to import express from NPM and then we export our own function to be used in any

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part of our application.