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Node

Node is an open-source, cross-platform JavaScript runtime environment.

Installation​

First, either install Node.js from their website, or use a Node version manager like nvm to install Node.js and npm.

tip

I recommend following these instructions for installation of Node and npm.

For using Node and npm, I use Hyper configured for git bash

Commands​

mkdir​

Creates a new directory. Ex. mkdir new-folder makes folder named "new-folder".

touch​

Creates a file. Ex. touch new-file.txt creates a file named "new-file.txt".

node​

Uses node to do something. Ex. node index.js runs the "index.js" file on your computer.

REPL​

REPL stands for Read Evaluation Print Loop. It runs js commands from within the node REPL terminal.

From your terminal, you can access the REPL by running the command node.

info

Can press "tab" twice to see all possibilities. Ex. type "console" then tab twice to see all options for that command.

To exit, hit CTRL+C twice.

Node.js API​

The Node.js API Docs describe what you can do.

You can import packages as CommonJS (CJS) or ES Module (ESM). ESM is newer and more people are using it although you will still find CJS all over the place.

note

To use ESM version, in "package.json" you need the line "type": "module",

FileSystem​

One popular package is the FileSystem package.

You use it (ESM) with:

import * as fs from "node:fs";

// example of usage
// copies file1.txt and names it file2.txt"
fs.copyFileSynce("file1.txt", "file2.txt");

NPM​

NPM stands for Node Package Manager. You will likely use it to startup your projects for both front and back-end.

npm init​

Inside your new project folder run npm init. This creates the "package.json" file in your project.

npm package installation​

If you want to install a package to use in your project, run npm install package-name. Ex. npm install superheroes installes the superheroes package, creating the "node_modules" folder and putting the package and any dependencies inside.

npm package update​

To update npm packages, there are a few ways to go about it. This link provides a good explanation of how it works.

ESLint​

ESLint is a tool for identifying and reporting on patterns found in ECMAScript/JavaScript code, with the goal of making code more consistent and avoiding bugs.

To use ESLint in your project, after initializing with npm init, run:

  1. npm init @eslint/config
  2. Select NPM (not browser)
  3. You will likely still have to edit your eslint config file after the fact, otherwise "process" will throw an error

ESLint Config File​

This file is .eslintrc.json.

If you are using node, add line "node": true, and remove line "browser": true,.

tip

I like to add a rule of "no-unused-vars": "warn"

Below is an example config file (what I use):

{
  "env": {
    "node": true,
    // "browser": true,
    "es2021": true
  },
  "extends": "eslint:recommended",
  "overrides": [],
  "parserOptions": {
    "ecmaVersion": "latest",
    "sourceType": "module"
  },
  "rules": {
    "no-unused-vars": "warn"
  }
}