JavaScript: Hey Y'all Watch This!

Ah, JavaScript! Like it or not, it’s a “tragically important” language that is “eating the world.” Hate it? Love it? Avoid it? Embrace it?

This talk is a parade of face-palm JavaScript fails, history of JavaScript, why it is the way that it is, how it's getting better, and bad jokes sure to get an eye-roll from everyone! Along the way, we may even learn a few mistakes to avoid and tips to make our own JavaScript less terrible!

Transcript

35. > const lol = a + b + c – f * ( n + o ); NaN
36. > NaN >= 0 false
37. > NaN <= 0 false
38. > typeof NaN number
39. ( a + b ) + c !== a + ( b + c ) > 0.1 + 0.2 === 0.3 false
40. > 0.1 + 0.2 0.30000000000000004
41. > Math.round(0.4999999999999999722444243843710864894092082) 0 > Math.round(0.4999999999999999722444243843710864894092083) 1 I’ve got 99 problems but JavaScript ain’t 1.0000000000000009
42. > [ 2, 10 ].sort() [ 10, 2 ]
43. > ['10','10','10', '10', '10'].map( parseInt ) [ 10, NaN, 2, 3, 4 ]
44. > typeof undefined // undefined > typeof true // boolean > typeof "hello" // string > typeof 1 // number > typeof {lol:true} // object > typeof [1,2,3] // object > typeof null // object
45. > null == 0 // false > null > 0 // false > null < 0 // false > null >= 0 // true > null <= 0 // true > Number( null ) // 0
46. > false > null > undefined > "" > 0 > NaN
47. > wat.test("javascript"); // true > wat.test("wat r u doin"); // false > const wat = /a/g;
48. // undefined function troll() { return { haha: "ha!" }; } troll(); // automatic semi-colon
49. const arr = []; arr[1] = 1; arr[3] = 2; arr[10] = 3; arr.length // 11 arr[-1] = 4; arr.s = 5; arr.length // 11
50. const person = { name: "David", speak: function() { console.log( `${ this.name } likes bacon.` ); } }; person.speak(); // David likes bacon
51. const person = { name: "David", speak: function() { console.log( `${ this.name } likes bacon.` ); } }; const davidSpeak = person.speak; // true davidSpeak === person.speak; // undefined likes bacon davidSpeak();
52. this.name = "Mike"; const fatArrowPerson = { name: "Jerry", speak: () => { console.log( `${ this.name } likes bacon, too.` ); } }; // Mike likes bacon, too. fatArrowPerson.speak();
137. To boldly go where NaN has undefined before!
140. 1982 Sinclair ZX Spectrum Graphics Emulator
141. 1982 Sinclair ZX Spectrum Graphics Emulator
142. 1982 Sinclair ZX Spectrum Graphics Emulator
143. 1982 Sinclair ZX Spectrum Graphics Emulator
144. 1982 Sinclair ZX Spectrum Graphics Emulator
146. Johnny-Five
147. Remote Garage Opener
149. Ken Wheeler @ken_wheeler : The Crossbro
151. Ken Wheeler @ken_wheeler :
152. Cody Lundquist @codyglundquist : Band.js – Music Composer
153. Lucas Timmons @lucastimmons : Miley Cyrus Scraper
154. Charter.js – Chord and Number Charts
161. Mobile Apps Automation / DevOps Command Line (CLI) Services