Intro to JavaScript

What is JavaScript?

JavaScript is an expressive programming language that powers a tremendous amount of the interactivity on the web, and increasingly powers servers behind the scenes. JavaScript written to run in a browser is often called "front-end" programming, and server-side JavaScript is usually considered "back-end" programming. In particular in front-end programming, JavaScript works hand-in-hand with HTML and CSS.

How to Create a JavaScript File

1. In Atom (or your preferred text editor), create a new file and name it main.js

2. The '.js' file extension name indicates that it is a JavaScript file

3. Create a new HTML file and name it index.html

4. Link your JS file inside of your HTML file

5. The line below should be right before your tag. This is because you want all of your other content (HTML and CSS) to run in the browser first.

   <script src="main.js"></script>

The Assignment - Complete the questions below

1. The below function does not work. The variable twoPlusTwo gets set to undefined. Refactor the function to make it work.

    function addNumbers(numberA, numberB) {
      console.log(numberA + numberB);
    }
   
    var twoPlusTwo = addNumbers(2, 2)
   
    console.log(twoPlusTwo) // 4
   

2. Write a function called yell that logs out an uppercase version of a string. Write a function called yell10 that uses your yell function to log out an uppercase version of a string 10 times.

3. Write a function called longest that returns the longest of two input strings or arrays.

4. Write a function called isVowel that takes a character (i.e. a string of length 1) and returns true if it is a vowel, uppercase or lowercase. The function should return false if the character is not a vowel.