Introduction to Node.js - Using Third-Party Modules with  CommonJS. In this video, I'm going to cover how to use a third-party module as part of the CommonJS system. At different stages of the video, on the right side of the screen, there will be a reference to related documentation. I will begin by installing the cli color module. This module is designed to help with colors, formatting, and other features in the console. In the terminal, I will type 'npm install cli-color'.

Now the installation is complete, and the modules listed as a dependency in the package.json file. In the index file, in order to use this module, I need to import it using the required statement. 'const clc = require(cli-color);'. The documentation for this module has many use case examples. In the index file, I will type console.log(clc.green()) and I will pass in the text of 'This is my green text'.

Now in order to execute this file in the terminal, I will type 'node index.js.' Now the terminal displays a green-formatted text that states, "This is my green text". Now this works, but the drawback is that the entry point file, which is the index file, isn't meant to be used as a module. If I were to import this third-party module into multiple files, my code would be overly repetitive. The solution is to integrate this third-party module into a custom module.

I have a file called Color.js, and at the top, I will type in the required statement for the cli-color module. To make this a little easier to use, I'm going to make a function. 'const setColorText = () with two parameters; color and text. Then using an arrow function, I will console.log() the same module method that I used earlier in the index file, but I will make this a little bit more dynamic; 'clc[color]() and then in the parentheses, I will pass through a template string with a string expression of '${text}'. So, why did I write the place holder method '[Color]' this way?

Earlier in the video, when I wrote this method, I used the dot notation for the color, but here I'm using the square bracket notation. That's because in JavaScript, when you want to call methods based on variable string values, when working with objects, you have to use square brackets.

If you're wondering what object am I referring to, modules are objects, and module methods are object properties. Does this mean that by using square bracket notation I could call module methods dynamically?

Yes. Now, in order to make this function available to use, I need to export it. module.exports = { } and I will export setColorText. Now, I'm ready to test out my color module. Going back to the index file, I'm going to delete the code that was previously written. Now I'm going to import the color module. 'const' using destructuring { setColorText = require()}.

Now I need the relative path of where the modules is located at. './color'. When importing a third party module, you do not need to include the file extension. Now I can use the 'setColorText()' function; setColorText() and I will pass in two arguments; the string 'blue' for the color parameter, and the string, "This is my blue text" for the text parameter. Going to the terminal, I will execute node on the index file again, and they in blue text, 'This is my blue text'. And that's it. Thanks for watching. @Cloud Academy.