Intro to Node Requiring and Using Node Packages

Learning Objective: By the end of this lesson, students will be able to require and use methods from an installed Node package.

Using a Node package

We’re going to make use of the validator package, so install it with:

npm i validator

Let’s explore how to require and use its validation methods in our project.

Requiring and using validator

Review package docs: Before using a package, it’s important to consult its documentation. Review the validator documentation on npm for detailed information and usage examples.
Require validator: At the top of server.js, bring the package into this file using CommonJS require() syntax:
```
const validator = require('validator');
```
Using const ensures that the validator variable won’t be reassigned accidentally.

📚 The require function loads the specified module. If a file path is given for a module (such as require('./myModule')), it directly loads the file. If a package name is provided (such as require('validator')), Node looks for the module in the node_modules directory.
Test a method: Select a method from the validator docs - let’s use isEmail(). We know from the docs that this method will return true or false depending on whether or not the value passed into this function is formatted as an email address.

Let’s try it:
```
console.log(validator.isEmail('test@example.com')); // Expected: true
console.log(validator.isEmail('not-an-email')); // Expected: false
```
This will log whether these provided strings are formatted as email addresses.
Run your code: Run the test file in the terminal.
```
node server.js
```
Check your terminal output to see the results!

🎓 You Do

Validate the casing of a string! Using the validator docs as your guide, try out the isUppercase() method.

Test if 'HI THERE' is uppercase, and log the result.

🧠 Some large packages even have their own website with documentation. Usually, these packages will have a link to their website on their npm registry page or any GitHub documentation they may have.