2. Setup a Node.JS environment and write your first function

These posts are designed to familiarize yourself with modern web development tools as well as teach you JavaScript. Here is a list of tools for getting started.

• The terminal app
• A package manager (homebrew on macOS, apt/dnf on Linux)
• NVM, node, and NPM
• Your favorite text or code editor, sublime text or vscode for me

macOS

Install homebrew, a package manager for macOS.

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
brew install nvm
nvm install --lts
which node

Linux (Debian/Ubuntu)

curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.1/install.sh | bash
source ~/.bashrc
nvm install --lts
which node

Install a text editor.

vscode (I use this at work usually)

# makes a folder called programming, you can name this whatever you'd like.
mkdir programming
# changes directory so that you will be in your programming directory.
cd programming
# create a file named add.js.
touch add.js

There is one feature in programming that is powerful enough to do almost anything you would want, especially in JavaScript. This feature is called a function.

Functions are just how you remember them in math class, ie input => output

Let's write our first function.

// Functions can be as easy as add.
const add = (x, y) => x + y;
// which is shorthand for
const add = (x, y) => {
    return x + y;
}
// or
function add(x, y) { 
    return x + y;
}
// it usually comes down to personal preference
// or sometimes performance

// Here is how you can use it.
const sum = add(1, 2);
// this function will print our result
console.log(sum) // 3
// you can also export functions so other files can see them
export add;

Think of a topic that interests you. I like music theory so I am going to write a simple function that tells me the fifth of any note I put in. Here is the code!

# create the file using your terminal, or text editor
touch musicTheory.js

Open the file in vscode or an editor of your choice.

# musicTheory.js
const getFifth = (note) => {
    // make the input note lowercase
    const lowerCaseNote = note.toLowerCase()
    // make a JS object of every input mapped to every output
    // plug your key in to get the value for the key
    const fifth = {
        c: 'g',
        g: 'd',
        d: 'a',
        a: 'e',
        e: 'b',
        b: 'f#',
        'f#': 'c#',
        gb: 'db',
        'c#': 'ab',
        db: 'ab',
        ab: 'eb',
        eb: 'bb',
        bb: 'f',
        f: 'c'
    }[lowerCaseNote]
    // format your output
    // to look like a note
    // ex Bb
    const formattedNote = `${
        fifth.charAt(0).toUpperCase()
    }${
        fifth.slice(1)
    }`
    // return your result
    return formattedNote
}

// how to use your function
const fifthOfGb = getFifth('gb')
// print to console
console.log(`The fifth of Gb is ${fifthOfGb}`)

Run node in your terminal to run the program.

node musicTheory.js # or whatever file name you chose

✨ Congratulations! you have written your first function. Tomorrow we will cover making your first Web App.