1. How I Learned to
Stop Worrying and
Love JavaScript

2. JavaScript
•Technically: ECMAScript
•ECMA-262 Specification (currently
v5.1)
•Weakly typed, interpreted, object
based, functional, prototypical

3. The History
•Created by Brendan Eich in 10
days
•Released in 1995 as part of
Netscape Navigator 2.0
•First standardised in 1997
•Also know as Mocha, LiveScript,

4. The Lineage
• Scheme: Functional
•Self: Prototypical
•Java: Ugly

5. The Problems
•The Name: JavaScript
•Early uses: sparkly text
•Lack of useful features in Browser:
e.g. XMLHttpRequest
•Slow

6. The Problems
•
Weird Shit:
NaN != NaN // true
[] + {} = 0
{} + [] = [Object object]
‘ ’ == ‘0’ // false
0 == ‘ ’ // true
0 == ‘0’ // true

7. The Problems
•The DOM
•Anyone can do it!
•jQuery

8. The Awesome
Functional Programming
• Functions are first class
• Incredibly powerful
• Closures / Lambda Calculus
• Callbacks: non-blocking
• Definitely not scripting!

9. The Awesome
Functional Programming
var array = [4, 8, 9, 1, 3, 9];
var weirdArray = (function() {
var newArray = [], i = 0, len = array.length;
for (i = 0; i < len; i += 1) {
newArray.push(array[i] + ‘ tiny monkeys’);
}
return newArray;
}());
console.log(weirdArray); // [‘4 tiny monkeys’, ‘8 tiny monkeys’, ..., ‘9

10. The Awesome
Functional Programming
var go = function (callback) { var logger = function (fn, name) {
var i, array = []; var start = new Date().getTime(),
for (i = 0; i < 2000000; i += log = function () {
1) { var end = new Date().getTime();
array.push(i); return name + ' took ' + (end - start) + '
} milliseconds';
};
return callback();
} return fn(log);
console.log(logger(go, 'go')); // ‘go took 114 milliseconds’

11. The Awesome
Prototypical Inheritance
• Objects without classes
• Powerful enough that it can pretty much emulate
classical inheritance
• Can reduce code significantly if used properly
• Can be a bit confusing at first

12. You Need to Know
• JavaScript is the new bytecode?
• Web apps are the future?
• Thin server-side architectures?
• Can’t be replaced?
• Windows 8
• Multi-processor support