• The data type that represents textual elements on the web
• Could be anything from the output of console.log to text on a web page

Concatenation

• Used to format text before it reaches its final destination

What is String Concatenation?

Combining two or more strings

• Feature that makes it easier to format text
• Can join a combination of variables and/or actual strings (also known as string literals)
• Concatenating strings will make a new string

Done with a + operator

• The addition operator is not just for numbers…

Using the + operator

let str1 = "Hello";
let str2 = "World!";

console.log(str1 + str2);
console.log(str1 + "Big" + str2)

Output:

HelloWorld!
HelloBigWorld

Adding spaces:

let str1 = "Hello ";
let str2 = "World!";

console.log(str1 + str2);
console.log(str1 + "Big " + str2)

Output:

Hello World!
Hello Big World!

Be careful with numbers!

• Numbers and strings both use the + operator
• Always keep everything the same data type

let num1 = 1;
let num2 = "1";

console.log(num1 + num2);
console.log (num1 + 1)

Output:

11
2

from: Working with strings [11 of 51] | Beginner’s Series to JavaScript

#!/usr/bin/env node

// from <https://youtu.be/EQMPAaAo6Fc>

// remember, var is function-scoped.
// this file is essentially one function
var hello = "Hello";
console.log(hello);
hello = "Hello world";
console.log(hello);

// using let (block scoped)
if (true) {
    let world = "Hello, World";
    console.log(world);
}

// const cannot be changed
const aaron = "Aaron";
console.log(aaron);

from Demo: Declaring variables [10 of 51] | Beginner’s Series to JavaScript (YouTube)

from Declaring variable: 9 of 51 (YouTube)

• Comments are lines in your code that you can see, but that do not get executed

• Single line comments
  • Add two // to the beginning of a line
  • Most editors will change the color of the line to grey
  • only applies to the current line - Any subsequent lines will not be commeneted out.
  • For example:

      // console.log(I am commented out");
      console.log("But I'm not!")
    

• Multi-line comments
  • Designed to comment out multiple lines
    • Does not require comment slashes on every line add a “/*” to the start of the comment and a */ to the end of it
    • Any text within those characters will be commented out
  • for example:

      /*
      console.log("I am commented out.")
      console.log("Me to!)
      */
      console.log("Not I")
    

• Comments in VS Code
  • Automatically comments out lines with a special keyboard shortcut.
    • Linux/Windows: ctrl+/
    • macOS: cmd+/
    • toggles comments off/on
• Words from the wise
  • “If your code needs a comment to explain what it does, it’s probably too complicated.” - Burke Holland, who once put comments on literally everything.
  • Take it easy with comments: To keep your code clean, try to steer clear of comments and instead make your code easier to read.
    from: Comments [7 of 51] | Beginner’s Series to JavaScript (YouTube)

// console.log("Hello, infinity and beyond!")

// -------------------------
//  this code reverses a string

/*
Multi-line comments!!
*/

from: Demo: Comments [8 of 51] | Beginner’s Series to JavaScript (YouTube)

#!/usr/bin/env node
// From: <https://www.youtube.com/watch?v=nQu2bbh4Vyc>
// Example #1
console.log('Example 1:');
console.log('Hello World🌎');
console.log(' ');

// Example #2
// Set some variables
const place = "World";
const greeting = "Hello";

console.log('Example 2:');
console.log('%s, %s,', greeting, place);
console.log(' ');

// Example #3 (Template literals - backticks)
console.log('Example 3:');
console.log(`${greeting}, ${place}`);

from: Creating your first application [6 of 51 ] (YouTube)

• Write, debug, and document your code
• source control management
• built-in terminal
• Customizable and extensible
• Free, cross-platform, and open-source

VS Code Extensions for JavaScript Developers

• ESLint
  • Find and fix problems in your JavaScript code before it hits production
• Prettier:
  • Automatic code formatter, so you don’t have to care about that extra space
• JavaScript (ES6) code snippets
  • Avoid redundant typing with shortcuts to most used code fragments

Node.js

• What is Node.js?
  • Node.js is a JavaScript runtime used to execute JavaScript code outside of a web browser
    from Building your toolbox [4 of 51] | Beginner’s Series to JavaScript (YouTube)

• Client: Runs in a web browser using scripts and tags. Has access to web page functions and objects - Document Object Model (DOM)
• Server: Requires Node.js and has acccess to built-in and third-party packages. Usually for building things like web services
• Third bullet point: You should always have 3 bullet points 😎
  from: Running JavaScript: browser or server: 3 of 51 (YouTube)