This document provides an introduction to JavaScript, covering key concepts like variables, data types, functions, and how the web works. It begins with introductions from the instructor and mentor. It then discusses programming fundamentals like defining problems, finding solutions, and implementing them in code. The document explains that JavaScript is used for both front-end and back-end development. It covers JavaScript variables, strings, numbers, Booleans, and basic functions. It provides examples and challenges for readers to practice the concepts. In the end, it discusses continuing education options through 1-on-1 mentorship.

1. Intro to JavaScript
May 2017
http://bit.ly/js-intro-dc

2. About us
We train developers and data
scientists through 1-on-1
mentorship and career prep

3. About me
• TJ Stalcup
• Lead DC Mentor @ Thinkful
• API Evangelist @ WealthEngine
• Github: tjstalcup
• Twitter: @tjstalcup

4. Our TA for tonight
• Randall Olade
• DC Mentor @ Thinkful
• Experience with .NET &
MEA(R)N Stack

5. About you
• Why are you here?
• Already work with developers
• Career Opportunity
• Next Facebook
• What is your programming experience?
• None
• 3 months self-taught
• Master (3+ Months)

6. Format for tonight
• Basics of how the web works
• Background about Javascript
• Review key Javascript concepts
• Practice with some challenges
• Next steps

7. What is programming?
Programming is writing instructions for a computer to
execute. Programming is problem-solving.

8. Programming is a process
1. Defining problems
2. Finding solutions to those problems
3. Implementing those solutions in a language your
computer can understand

9. Perception

10. Reality

11. How the web works
Type a URL from a client (e.g. google.com)
Browser communicates with DNS server to
find IP address
Browser sends an HTTP request asking
for specific files
Browser receives those files and renders
them as a website

12. Clients / Servers
Client (sends requests)
Frontend Developer
Manages what user sees
Server (sends response)
Backend Developer
Manage what app does

13. Example: facebook.com
HTML, CSS, &
Javascript render
interactive newsfeed
Algorithm determines
what’s in your feed
Request
Get data about your
friends’s and their posts
Open browser
and navigate to
facebook.com
Application Logic
Database
Response
Client Server

14. Brief history of Javascript
• Written by Brendan Eich in 1995 for Netscape
• Initial version written in 10 days
• Completely unrelated to Java, but maybe named after
it to draft off its popularity
• Over 10 years, became default programming
language for browsers
• Continues to evolve under guidance of ECMA
International, with input from top tech companies

15. Javascript is extremely popular

16. This makes it a good place to start
• Has large community of developers, libraries and
frameworks
• Lots of job opportunities
• Also the syntax is easier to understand for first-time
developers

17. Are we learning frontend or backend?
100% of client-side web development is in Javascript.
You can also use Javascript to write server-side code
thanks to Node.js. So technically both!

18. Concepts we’ll cover
• Variables
• Data types: strings, numbers, booleans
• Functions

19. Note on where to write you code
When working as a programmer, you’ll use a text editor
or an “Integrated Development Environment” (IDE).
Tonight we’re using JSBin so we can skip setup, see
results immediately and easily share code

20. Javascript variables
• A variable is a name that is attached to a value — it gives
us a shorthand way to refer to the value elsewhere
• Helps us remember things while we’re executing a
program: “managing state”
• Example on JSBin: http://bit.ly/js-example-one

21. Examples
• Declaring variable: var firstVariable;
• Assigning value: firstVariable = 6;
• Retrieve value: alert(firstVariable)
Example on JSBin: http://bit.ly/js-example-two

22. Best practices for naming variables
• Names should be (extra) descriptive: “numberOfCats”
is better than “x”
• Use camelCasing where first word starts with lower
case, subsequent words are upper case
• Must start variable names with a letter

23. What values can be assigned to a variable?
• String
• Number
• Boolean
• Also Null, Undefined, Arrays, and Objects

24. Introducing strings
We use strings a lot. Strings are created with opening
and closing quotes (either single or double):
var foo = ‘bar’;
var bar = “foo”;

25. Combining (or “concatenating”) strings
Javascript lets you combine two strings by using the +
operator. Let’s try it in the console!
var host = “Thinkful”;
var className = “Intro to Javascript”;
console.log(className + “ with “ + host);
=> Intro to Javascript with Thinkful

26. Quick challenge
• Open JSBin in your browser
• Store your first name in one variable
• Store your last name in another variable
• Combine the two and log your full name

27. Introducing numbers
The number type in Javascript is used to represent all
kinds of numbers, including integers and decimals.
var integerNumber = 3;
var floatingPointNumber = 3.00;

28. Quick challenge
• Open JSBin
• Store two numbers in two different variables
• Add the two numbers
• Multiply the two numbers

29. Introducing booleans
Boolean is just a fancy word for “true” or “false”
var loggedIn = true;
if (loggedIn == true) {
alert(“loggedIn was set to true!”)
}

30. Basic functions
A function lets you separate your code into bite-sized
pieces which you can use over again.
When you write a function to use later, you are
“declaring” it. When you use (or run) that function you
are “calling” it.

31. Example
Declaring a function
function doSomething() {
alert(“Done!”);
}
Calling a function
doSomething();

32. More about basic functions
• Functions can save us time because we can use them
over and over code. They are like building blocks.
• Functions make your code more organized and easier
to read
• Javascript has many built-in functions — you’ve already
used a couple!
• In writing less trivial programs, you’ll write many, many
functions

33. Challenge #1
• Go to JSBin.com, make sure auto-run with Javascript
isn’t selected
• Declare and call this function:
function myFirstFunction() {
console.log(“Hello World!”);
}
myFirstFunction();
• Click “Run with JS” to see output in console

34. Challenge #2
• Open JSBin
• Write a function that logs your name
• Write a function that adds two numbers and logs the
result
• Call both functions

35. More advanced functions — parameters and return
• We can “give” a function some values to use. We call
the values we send into a function “parameters”
• We can have a function give a single value back. We
use a “return” statement to do that.
• We define what parameters the function accepts when
we declare the function.
• We send the actual parameters when we call the
function — we put those parameters in the parentheses.
Example: addTwoNumbers(2, 3);

36. An example
function addTwoNumbers(firstNumber, secondNumber) {
return firstNumber + secondNumber;
}
var result = addTwoNumbers(2, 3);
alert(result);

37. Challenge
• Open JSBin
• Write a function that takes your first name and your last
name as two parameters
• Return a string with your full name
• Call that function

38. Ways to keep learningLevelofsupport
Learning methods

39. 1-on-1 mentorship enables flexibility
325+ mentors with an average of 10
years of experience in the field

40. Support ‘round the clock

41. Our results
Job Titles after GraduationMonths until Employed

42. Try us out!
• Initial 2-week trial
includes six mentor
sessions for $50
• Learn HTML/CSS and
JavaScript
• Option to continue
onto web
development
bootcamp
• Talk to me (or email
tj@thinkful.com) if
you’re interested