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Now that we extracted the configuration,

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What we can also do still here in app.js,

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is we can extract our custom middleware.

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We are using a bunch of middleware

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from third-party packages,

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like the URL encoded body parser,

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serving static files,

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CSRF protection and the session.

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We also got a custom middleware here.

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And of course we can write that code here,

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where we needed,

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or we store that in a separate file

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to again make this app.js file leaner.

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And I'll do that,

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I'll add a middlewares folder,

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which again is not a reserved name,

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you can use whichever name you want,

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but it is a common name.

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And in there I'll add my auth.js file

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or auth-middleware

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if you wanna be very clear about what's inside

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since this is a file that shoots the (indistinct)

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the authentication related middleware.

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And in this case,

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I only have one authentication related middleware,

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but if you had authorization as well,

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and you would be doing that

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in a separate middleware function,

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you could also have multiple middleware functions.

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So here I am now going to

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extract this async function from app.js,

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I'm going to cut it

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and add it here in auth-middleware js.

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Now this was an anonymous function

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and since I'm now defining it stand alone

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and I wanna use it in a different place,

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this can't stay an anonymous function,

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it needs a name now instead

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so that we can refer to it by that name

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in other places of our code.

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And here I'll name it, auth,

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but the name is totally up to you.

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And then all export it, just like this.

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I'm going to export this auth function

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from that auth-middleware file

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so that we can use it in other files.

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Because as you learned before,

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if you wanna use a feature like a function

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from file A in file B,

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then you have to import it in file B.

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You can't just use it by its name,

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instead you have to import it first.

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So in this case, app.js is file B

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where I wanna use it,

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so there I now do import my auth middleware.

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You can name this constant however you want

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by requiring ./middlewaresauth-middleware.

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And then this authMiddleware function

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is what I parse to app use.

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Now, unlike csrf or urlencoded

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and all these other

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third-party middlewares I added,

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this doesn't need to be executed.

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Because these functions

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which are coming from third party packages

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are actually not the middlewares themselves,

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instead these are in the end,

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all configuration functions

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which take configuration options

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at least optionally,

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in case of csrf I'm not parsing any,

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but if we could configure this as well.

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And therefore it's these configuration functions,

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which are provided by the third-party packages,

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and that's why I'm executing them here in app use.

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Because when we execute this configuration function,

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that will return us the actual middleware

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and it's then the returned middleware

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that is registered.

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In case of authMiddleware,

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I got no configuration function wrapper.

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Instead there,

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I directly defined the middleware function itself,

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the function that takes req, res and next.

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And I'm exporting this function

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so therefore this should not be executed by us,

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but instead by express, once we got incoming requests,

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this is the middleware function already.

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That's why I'm not executing

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the auth-middleware function here,

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but why I'm just pointing at it

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because I don't wanna execute it

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instead that is the middleware function

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which I wanna register with express

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so that express executes it in the future

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once I got incoming requests.

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00:04:10,480 --> 00:04:12,260
And now if we save that,

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we can also quickly test this

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00:04:14,490 --> 00:04:18,399
and try logging in here real quick.

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And that still seems to work just fine.

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So that authMiddleware also works

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and now I extracted this as well.

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00:04:27,040 --> 00:04:30,380
And with that, we of course could do more,

104
00:04:30,380 --> 00:04:33,020
but I would say this is enough right now

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and that app.js file already got a bit leaner

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and our code got more structured.

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Because now for example,

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if we wanna work on the session configuration

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or on the authMiddleware,

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we don't have to search for the relevant parts

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here in app.js

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instead we can directly go to the relevant files,

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which are then way leaner

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and way more structured.

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That's the idea behind refactoring in the end.

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Now with all of that done,

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let's come back to our routes.

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We already split the routes into multiple files,

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but these files are still relatively large.

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And if you would have a look at the different routes

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that are registered there,

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you would find some code duplication in there.

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For example that session error management here.

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And whenever you see code duplication,

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that's a good indicator

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that more refactoring could be done

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and that you might be able to make your code slimmer

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and easier to manage.

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00:05:35,260 --> 00:05:38,210
So therefore this session usage

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00:05:38,210 --> 00:05:40,430
for error management thing

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00:05:40,430 --> 00:05:44,410
is one aspect that could probably be outsourced

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and we're going to do that.

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But in addition to that

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00:05:47,780 --> 00:05:49,615
what we also have in those files

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00:05:49,615 --> 00:05:52,210
is a lot of logic related

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to working with the database.

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We're doing all the database operations in there

138
00:05:57,230 --> 00:06:01,040
and even though those operations aren't too difficult,

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00:06:01,040 --> 00:06:03,050
it's still a lot of logic

140
00:06:03,050 --> 00:06:05,610
that lifts in this routes folder

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or in these routes files.

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And as always that's not horrible,

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00:06:10,990 --> 00:06:15,990
but it is something you could consider doing differently.

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00:06:16,280 --> 00:06:18,190
And that's what I'll dive in next

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before we then there after

146
00:06:19,710 --> 00:06:22,960
explore more refactoring potential

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that we might have in these files.