NodeJS and Built in Modules

A Closer Look at NodeJS

We’ve installed node packages and set up node projects. But we haven’t gotten into the fact that node is a runtime environment

• Every file in a node application is considered a module
• Variables and Functions in each file are scoped to that file

Activity 1: Set up a node project

• initialize a node project with the init command
• create an index.js or app.js file with a console.log() to make sure your scripts work
• also set up git and add a .gitignore (hiding node_modules)
• set up a start command in your scripts

Activity 2: Create a module

• Create a logger.js file and in it write a custom logger function that takes a variable
• set it to module exports module.exports module.exports = log`
• require it in the app.js file `const log = require(‘./logger’)
• use the logger in the app file

Activity 3: Refactor for es6 imports

• es6 import/export syntax is another way to use modules
• add "type": "module" to your package.json file
• remove module.exports = log and add export { log } or export default infront of the function
• use import {log} from './logger' syntax to import it
• try setting an alias with “as”

Activity 4: Built in Modules fs

• Use fs.writeFile() to add contentent to a: json, txt, and md file
• use fs.readFile() to log the content to the console