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In this video, we are going to learn Node.js modules.

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So what is a Node.js module?

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We can consider Node.js modules to be the same as JavaScript libraries.

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It is a set of functions that we want to include our applications.

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So let's make this logger file as a Node.js module.

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As you remember that in the last video we have created the local JS and local function, but now we

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can create these logger operation as a Node.js module.

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In order to do that, we are going to change these method with the method which they should be the exports.

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You would.

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Yes, exports cost.

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And I would like to change the name of the method which is the right logo.

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And now we don't need to invoke this function inside of the file.

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It should be export, not exports.

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So as you can see that this is the method body that we can use the export keyword and it is basically

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exporting these functions to the other files.

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That means this becomes a Node.js modules.

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So now how we can use these Node.js module into other files in order to do that, please create an index

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case and into the index case.

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I'm going to write a function, for example, main function.

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And in the main function, we can basically make our log operation, which is the main function.

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Starts.

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And after that, we can.

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Bite the right look.

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So when I write the right look, operation method, as you can see that it is going to add inputs to

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a statement from the logger file.

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So if you click this IntelliSense keyword, you can see that it is basically import logger class and

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logger JavaScript file and import write log method.

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So by this way, we can use this method into our main function from the index JS file.

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So in order to do that, I'm going to pass two parameters.

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I would like to paste two parameters.

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So instead of we are getting the arguments, we can change these local function to get the name and

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surname as a parameter.

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So let's make a little bit change.

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So name and surname is created as a parameter for this function.

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So in order to use this function, I'm going to set a these name and surname from the parameters.

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Now we can remove this line of code.

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Okay.

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So as you can see that this very basic Node.js model.

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It is getting the name and surname as a parameter and it will make the log message.

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But we expose this right lock method into the indexes and to do so in order to use this function.

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As you can see that we should provide the name and surname.

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So I'm going to give my name and surname basing this function.

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And after that, we will call these mean method to invoke all these operations.

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Okay.

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Now I'm going to run the node command node.

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Next JS file and see what's happened.

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So when we run this not comment, we get exception, which is the cannot use import statement outside

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a module.

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So what is exception is throwing?

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So if you scroll up you can see the warning to load an is module.

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We should set the type module in package JSON file.

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So this is related with the module explanation in the Node.js function that I'm going to explain in

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the upcoming videos.

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But I can say that Node.js has two types of modules.

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One is the common JS.

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Another is the script name version.

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So we will use a script modules.

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So to activate it, we should set the type module in the package JSON file.

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So let me add the package JSON file for now and I will explain in the outcome could use.

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But you can add the package JSON file after that.

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We can set the type and you can see that there is two types of Node.js modules, common JS and module.

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We are going to use module in order to activate the latest script codes.

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So let's save this file and this time in the local file can be exported method with using the export

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keyword and after that index file can be used this local operation with importing the logger file.

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Okay, now after that, let's run this command again.

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Note index is hit enter.

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So this time again we got another exception.

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So this is also important exception.

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So as you can see the message did you mean to import logs?

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So sometimes in some cases it is explicitly not that the full folder name.

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So that means when we are importing this logger operation, we should provide the logger dot js file.

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So this is important.

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Please save this file import statement because when we are adding these import statement with using

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the values to do code IntelliSense, it doesn't include this JavaScript file and we should add the JavaScript

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file explicitly.

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So after that, after make this change and save these indexes file.

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If you run the note indexes comma hit enter.

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We can get the success response in our case.

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So as you can see that the first log is come from the main function starts and the second log is comes

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from the our right log operation, which is exposing from logs.

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We can right click go to definition and see the log operation, which is your name and surname is Mammoth

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Square.

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Okay.

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As you can see that we understand how Node.js model works and how we can use modules in our Node.js

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application.

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If we examine the Node.js lambda function, for example, I have put the calculator lambda function

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code in here.

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You can see that we have all of the exposed 100 method in a common module version.

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You can see that this time it is using exports and it is exporting 100 method.

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So if you look at the lambda function, this is the runtime Node.js runtime is running the handle method

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when invoking any location comes to lambda function.

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So we are exposing these 100 method with using these exports 100 method body.

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But we can change these export 100 which we must equip Node.js module with adding package JSON we will

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do in the upcoming videos.

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But if we examine the our calculator JavaScript file of the lambda function, it is basically exports

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the one handed method after that one event in the lambda function.

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This will trigger to handle method with incoming event JSON object.

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So we have learned the basics of lambda node.js functions and the modules.

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As you can see that we have create a Node.js module and use it this module into our index file.