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Meetup-js-072315

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Javascript for beginners session 03.
Variable types, naming, dynamic typing
Promoted through meetup.com/Tacoma-JS
and hosted by kofc809.org

Published in: Software
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Meetup-js-072315

  1. 1. Javascript computer programming for beginners S03 7/23/2015 1kofc809.org
  2. 2. Beginning Javascript Moderator: Joe Devlin 7/23/2015 2kofc809.org
  3. 3. Beginning Javascript Today’s Event hosts • Knights of Columbus Tacoma Council 809 7/23/2015 3kofc809.org
  4. 4. A word from our hosts • Knights of Columbus Tacoma Council 809 www.kofc809.org o Founded in 1882 o Dedicated to “Saving Lives and Changing Lives” o Promoting strong families through charitable giving and a AAA rated life insurance and annuity program. o Local projects Habitat for Humanity Build, Blood Drive, Ultrasound for pregnancy care & 4US.org, Coats for Kids, Wheelchair Mission. 7/23/2015 4kofc809.org
  5. 5. Beginning Javascript Access this slideshow at: http://www.vividventures.biz/d/?q=javascript 7/23/2015 5kofc809.org
  6. 6. Introduction •Joe Devlin - moderator o Member of St Patrick’s Parish and K of C council 809 o Working as a web host for small to medium sized businesses. oInterested in Javascript for the obvious reasons that it is a must for web development, plus for the purposes of getting people together to code; JS is a universal standard that comes with freely downloadable browsers and tools. We can easily collaborate. 7/23/2015 6kofc809.org
  7. 7. Time management 7/23/2015 7kofc809.org Present Code Discuss
  8. 8. 7/23/2015 8kofc809.org Schedule 1400-1410 Setup 1410-1420 Introduce ourselves 1420-1500 Set up: Teamtreehouse, codepen.io, github, git 1500-1510 Download git --local-branching-on-the- cheap 1510-1530 Teamtreehouse “Javascript Basics – Strings and Numbers; Spaces, tabs & new lines” 1530-1600 Variable Typeof’s,
  9. 9. Engagement 7/23/2015 9kofc809.org • To make our meetup more personable I am inviting members to add links to their meetup.com introduction that directly references something related to Javascript or programming for example codepen.io or github.com.
  10. 10. Attendee Introduction • Let each of us introduce ourselves o My name is ____________. (First name) o My github username is ______________. o My codepen username is _____________. o I (have/have not) updated my meetup profile with above links. o The editor that I am using today is ____________. o I am working on a Mac / PC / Linux 7/23/2015 10kofc809.org
  11. 11. Take away for today 7/23/2015 11kofc809.org • Pierce County Library apply o Teamtreehouse.com o https://teamtreehouse.com/gateways/pierce_county_public_library/signup o Why? Teachable, repeatable, powerful
  12. 12. Take away for today 7/23/2015 12kofc809.org • Set up browser bookmarks in folders as follows:  Tacoma-JS  https://teamtreehouse.com/gateways/pierce_county_pu blic_library/signup  http://codepen.io/NorthDecoder/  https://github.com/NorthDecoder  https://gist.github.com/NorthDecoder  http://git-scm.com/ o Beginner Sessions o 03
  13. 13. Take away for today 7/23/2015 13kofc809.org • Set up browser bookmarks in folders as follows:  Tacoma-JS Beginner Sessions  03  https://teamtreehouse.com/library/javascript- basics/storing-and-tracking-information-with- variables/naming-variables
  14. 14. Take away for today 7/23/2015 14kofc809.org • (if you already have these NO need to repeat  ) • In your finder or explorer in ‘My Documents’ create folders  manuals o Javascript reference the books o Beginning Javascript 4th Edition pdf o from http://it-ebooks.info/book/1068/ o Javascript Step by Step 3rd Edition pdf  from http://it-ebooks.info/book/3481/ o git reference the book o Version Control with Git from http://www.it-ebooks.info
  15. 15. git --local-branching-on-the-cheap 7/23/2015 15kofc809.org • http://git-scm.com/ try •Git is a free and open source distributed version control system designed to handle everything from small to very large projects with speed and efficiency. •Download
  16. 16. Requirements – just a reminder 7/23/2015 16kofc809.org HTML Validator JS - valid Test http://validator.w3.org/nu/ http://www.jslint.com/ http://www.jshint.com/ Design inputs to confirm the expected output. TDD pdf
  17. 17. Course – Teamtreehouse 7/23/2015 17kofc809.org • Teamtreehouse.com (TTH) o TTH Library search for “Javascript Basics – Naming Variables” • You can: • review videos at any time • retake the tests • save workspaces • earn badges !
  18. 18. Course – Variable Types 7/23/2015 18kofc809.org • Example o codepen.io, NorthDecoder  http://codepen.io/NorthDecoder/ o Introduction to Javascript variables and types  http://codepen.io/NorthDecoder/pen/OVRQMG • http://www.ecma-international.org/ecma-262/5.1/#sec-8
  19. 19. 7/23/2015 19kofc809.org Variable: Types Reference: Javascript Step by Step 3rd Edition pdf Chapter 4 p. 41 http://www.ecma-international.org/ecma-262/5.1/#sec-8 • Variable types: o Undefined o Null o Booleans o Strings o Numbers o Objects o Command: var theTypeIs = typeof(aVariable);
  20. 20. 7/23/2015 20kofc809.org Variable: Dynamic Typing Reference: Dynamic typing vs. static typing http://courses.cs.washington.edu/courses/cse341/04wi/lectures/13-dynamic-vs-static-types.html https://en.wikipedia.org/wiki/Type_system • Dynamic Typing: type-incorrect operations are caught during program execution, rather than during a type checking phase that precedes execution. • Try this in codepen: http://codepen.io/NorthDecoder/pen/KpxwOX var myNumber = 12; var theTypeIs = typeof(myNumber); alert(myNumber + ' is a: ' + theTypeIs); myNumber = "Text";//new value type assigned to same variable theTypeIs = typeof(myNumber); alert(myNumber +' is a: ' + theTypeIs);
  21. 21. 7/23/2015 21kofc809.org Variable: Dynamic Typing • Where is the dynamic variable type bug in this code? var debugLevel = 1;//0 = no messages //1 = console messages //2 = alert messages switch (debugLevel){ case "0" : break; case "1" : console.log("Why does this not print?"); break; case "2" : alert("Why does this not print?"); break; } Reference: Checking types in Javascript http://tobyho.com/2011/01/28/checking-types-in-javascript/
  22. 22. 7/23/2015 22kofc809.org Variable: Dynamic Typing • The dynamic variable type bug removed var debugLevel = 1;//0 = no messages //1 = console messages //2 = alert messages switch (debugLevel){ case 0 : break; case 1 : console.log("Casing on number 1 debugLevel."); break; case 2 : alert("Casing on number 2 debugLevel."); break; } Reference: Checking types in Javascript http://tobyho.com/2011/01/28/checking-types-in-javascript/
  23. 23. That all folks ! 7/23/2015 23kofc809.org • Thank you for attending the meetup.

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