WEBVTT

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Hi everyone!

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In this video I will show you the some options to reduce the amount of data.

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Okay, right now we already know.

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The first option.

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First option we were using DTO to customize the response.

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Right.

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Customize the response right here.

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And the second option is using the technique called serialization from NestJS documentation okay.

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This is the second option I will show you in this video if you click on the serialization topic right

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here and you have some exclude property, it will exclude property.

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something like this.

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Okay, you can see it's very easy to exclude some property like example like password, because when

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we respond data we don't need to return the password.

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Right.

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So this is the second option.

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But I don't like this option at all.

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I prefer using a DTO.

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The reason because when you work with this difference framework and in the MVC architecture, it's a way

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more prefer to use the DTO to reduce the amount of data.

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Okay, this is hiding of data.

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Okay, this line will be headed up.

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Like this here will be reduced.

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So.

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But anyway, let me show you how we can use last excluded property.

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Okay, let's see if it works or not.

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If I go to.

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Let me see the schema.

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Okay.

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Now you can see it.

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It use the exclude directly inside the user entity right here okay.

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Now let me use directly inside the schema and import that from class transformer.

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Okay.

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And this is not complete.

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We must use something called use interceptor with class serialize interceptor right here.

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I will copy that also.

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And I will go to the controller and import that.

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Right.

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Like this.

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Import and import the class.

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Okay.

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We already know the decorator call "@UseInterceptor", right?

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This will help me use the interceptor.

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And what is inside the class serializer?

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Interceptor.

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Also, actually, as a developer, we don't need to care about that.

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We only need to know when we @Exclude property.

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We must use the interceptor with the class serializer.

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Interceptor like that.

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Okay.

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And this will be enough.

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Okay.

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Now inside the get all method right now, I will remove, I will comment and I will return the

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directly the post

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With any.

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Okay, let's see what happens.

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If I go to the post and I send a request, now you can see it.

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Return for me is something like this.

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That's not what we want, right?

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I want it will return only the data title, it don't return the @Exclude property description.

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Okay, I want only show the title.

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You can see it's not work. I don't know why it's not work with the MongoDB, but in

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the SQL.

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Okay.

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Inside a normal SQL this line will be worked.

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But I don't know why this case didn't work right now, but anyway, don't worry about us.

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I will rollback the code

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But even if the line work.

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Okay?

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Even if.

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This work, I will not also use that.

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Why?

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For example.

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Later I will have a some property.

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For example like role.

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Okay, let's assume I have a role with string.

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Okay.

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And if I mark it @Exclude

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What happened right now?

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Well, if for example like staff of the company.

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company

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I don't want

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The staff can see the "role".

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But if I'm an admin.

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Okay, if I am the admin, I want it see the "role"

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Right.

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But in this case, if we you directly the @Exclude.

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I don't have any chance to do this stuff.

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I don't have a ability to check the condition in right here.

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So for that reason I will not use the @Exclude

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Okay.

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This is the downside of this approach.

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And for that reason, I will use the first approach, using the DTO like this.

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Okay.

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Let me run back code you don't need to write the code with me in this video.

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Okay.

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Then we discard the changes.

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Now.

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I will use this approach with you using the response DTO.

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Okay.

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But the downside of this ResponseDTO here, it will have some duplicate code like this.

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Right.

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Because this is only what we need.

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But we use something like here to convert it inside the DTO.

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This will increase the code base.

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Right.

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The number of codes I don't want that.

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So for that reason in the next video I will show you how we can customize this thing.

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So I will see you in the next video.