Javascript: Understanding the weird parts

Javascript started out as a language used to make web pages dynamic, now Javascript runs almost everywhere. The sad part is that a lot of developers only learnt javascript to get things done and don't have an understanding of what happens under the hood. In this presentation, I talk about a few of the nuances of Javascript that give developers the popular "that's weird!" moments.

Presented at Cotta & Cush Tech Talks
Tech Talks is a weekly internal event at Cotta & Cush Limited featuring technical presentations, app reviews among other discussions

Transcript

1. JavaScript: Understanding the weird parts
2. JavaScript?
3. JavaScript? - Started out as language to make web pages dynamic
4. JavaScript Everywhere!
5. The Sad Part
6. Weirds
7. Weird 00
8. Weird 01
9. var foo = ‘1’ + 2; console.log(foo); var data = data || {}; console.log(data);
10. Weird 02
11. var a; console.log(a); if (a === undefined) { console.log('a is undefined!'); } else { console.log('a is defined!'); }
12. Weird 03
13. var Tony = { firstname: 'Tony', lastname: 'Alicea', address: { street: '111 Main St.', city: 'New York', state: 'NY' }, fullname: function(){ return firstname + ‘ ’ + lastname; } }; var firstnameKey = ‘firstname’; console.log(Tony.firstnameKey); console.log(Tony.firstname); console.log(Tony.fullname);
14. Weird 04
15. function a() { console.log(this); this.newvariable = 'hello'; } var b = function() { console.log(this); } a(); console.log(newvariable); // not good!
16. Weird 05
17. var foo = function() { var bar = 'baz' return { bar: bar } } console.log(foo());
18. Weird Undefined
19. Get JavaScripty!
20. Questions?
21. Thanks!