How to stop to worry and starting to love JavaScript

1. JavaScript Survival Guide
Roma,
Giordano Scalzo 5 marzo 2011

2. I’m not a guru!

3. I’m still learning

4. Java/C++ guy in the past

5. Ruby/ObjectiveC guy in the present

6. Why to learn JavaScript?

7. JavaScript isn’t this anymore

8. JavaScript is everywhere!

9. JavaScript is popular!

10. JavaScript is trendy!
Technology Radar

11. JavaScript is trendy!
Technology Radar

12. It should be easy...

13. Hacked by Brendan Eich in one week...

14. At the beginning...

15. after a while...

16. traps everywhere..

17. traps everywhere..

18. and...

19. :-(

20. and so...

22. Back to study!

23. Started a notebook...

24. Essential
Scope

25. function sum(x, y){
// implied global
result = x + y;
return result;
}
{antipattern}

26. Global variables are evil!

27. Variables clash

28. Always declare variables with var
function sum(x, y){
var result = x + y;
return result;
}
{pattern}

29. function foo(){
var a = b = 0;
//...
}
{antipattern}

30. b become global
function foo(){
var a = (b = 0);
//...
}
{antipattern}

31. don’t use assign chain in definition
function foo(){
var a, b;
a = b = 0;
//...
}
{pattern}

32. Hoisting
myname = "global"; // global variable
function func(){
// code...
console.log(myname); // "undefined"
// code...
var myname = "local";
console.log(myname); // "local"
}
func();
{antipattern}

33. Hoisting
myname = "global"; // global variable
function func(){
// code...
console.log(myname); // "undefined"
// code...
var myname = "local";
console.log(myname); // "local"
}
func();
{antipattern}

34. Hoisting
myname = "global"; // global variable
function func(){
// code...
console.log(myname); // "undefined"
// code...
var myname = "local";
console.log(myname); // "local"
}
func();
{antipattern}

35. Hoisting
myname = "global"; // global variable
function func(){
var myname = "declared";
// code...
console.log(myname); // "declared"
// code...
myname = "local";
console.log(myname); // "local"
}
func();
{pattern}

36. Against minimum vertical
distance principle
“Variables should be declared as close to
their usage as possible”
Robert C. Martin - Clean Code

37. Single var pattern
function func(){
var a = 1,
b = 2,
sum = a + b,
myobject = {},
i,
j;
// function body...
}
{pattern}

38. Don’t forget comma otherwise...

39. ... variables become globals

40. Essential
Literal and Constructor

41. In JavaScript almost everything is an object

42. It’s easy...
var person = new Object();
person.name = "Scott";
person.say = function(){
return "I am " + this.name;
};
console.log(person.say());

43. but wrong! :-(
var person = new Object();
person.name = "Scott";
person.say = function(){
return "I am " + this.name;
};
console.log(person.say());
{antipattern}

44. var person = {};
person.name = "Scott";
person.say = function(){
return "I am " + this.name;
};
console.log(person.say());
{pattern}

45. What if we need similar objects...
var person = {};
person.name = "Scott";
person.say = function(){
return "I am " + this.name;
};
console.log(person.say()); // I am Scott
var otherPerson = {};
otherPerson.name = "Tiger";
otherPerson.say = function(){
return "I am " + this.name;
};
console.log(otherPerson.say()); // I am Tiger

46. A lot of duplication
var person = {};
person.name = "Scott";
person.say = function(){
return "I am " + this.name;
};
console.log(person.say()); // I am Scott
var otherPerson = {};
otherPerson.name = "Tiger";
otherPerson.say = function(){
return "I am " + this.name;
};
console.log(otherPerson.say()); // I am Tiger

47. Duplication is evil!

48. Custom Constructor Functions
var Person = function(name){
this.name = name;
this.say = function(){
return "I am " + this.name;
}
}
var person = new Person("Scott");
console.log(person.say()); // I am Scott
{pattern}

49. Behind the scenes...
var Person = function(name){
// var this = {};
// this.prototype = {constructor: this}
this.name = name;
this.say = function(){
return "I am " + this.name;
};
// return this;
};
{pattern}

50. So, at the end...
var Person = function(name){
this.name = name;
this.say = function(){
return "I am " + this.name;
};
};
var scott = new Person('Scott');
var tiger = new Person('Tiger');
console.log(scott.say());
console.log(tiger.say());
{pattern}

51. What if we forget new?

52. this will point to global object
var Person = function(name){
this.name = name;
this.say = function(){
return "I am " + this.name;
};
};
var scott = new Person('Scott')
var adam = Person('Adam')
console.log(typeof scott); //object
console.log(scott.name); // Scott
console.log(typeof adam); //'undefined'
console.log(window.name); // Adam

53. this will point to global object
var Person = function(name){
this.name = name;
this.say = function(){
return "I am " + this.name;
};
};
var scott = new Person('Scott')
var adam = Person('Adam')
console.log(typeof scott); //object
console.log(scott.name); // Scott
console.log(typeof adam); //'undefined'
console.log(window.name); // Adam

54. Enforce new pattern one:
naming convention

55. var Person = function(name){
var that = {};
that.name = name;
that.say = function(){
return "I am " + that.name;};
return that;
};
var scott = new Person('Scott')
var adam = Person('Adam')
console.log(typeof scott); //Object
console.log(scott.name); // Scott
console.log(typeof adam); //Object
console.log(adam.name); // Adam
{pattern}

56. var Person = function(name){
var that = {};
that.name = name;
that.say = function(){
return "I am " + that.name;};
return that;
};
var scott = new Person('Scott')
var adam = Person('Adam')
console.log(typeof scott); //Object
console.log(scott.name); // Scott
console.log(typeof adam); //Object
console.log(adam.name); // Adam
{pattern}

57. Drawback: we loose prototype reference :-(
var Person = function(name){
var that = {};
that.name = name;
that.say = function(){
return "I am " + that.name;
};
return that;
};
Person.prototype.iamhumanbeing = true;
var scott = new Person('Scott')
var adam = Person('Adam')
console.log(scott.iamhumanbeing); // undefined
console.log(adam.iamhumanbeing); // undefined

58. Drawback: we loose prototype reference :-(
var Person = function(name){
var that = {};
that.name = name;
that.say = function(){
return "I am " + that.name;
};
return that;
};
Person.prototype.iamhumanbeing = true;
var scott = new Person('Scott')
var adam = Person('Adam')
console.log(scott.iamhumanbeing); // undefined
console.log(adam.iamhumanbeing); // undefined

59. Interm!zo
Prototype property

60. Define ancestors chain
var foo = {one: 1, two: 2};
var bar = {three: 3};
foo.__proto__ = bar;
console.log(foo.one);
console.log(foo.three);

61. Define ancestors chain
var foo = {one: 1, two: 2};
var bar = {three: 3};
foo.__proto__ = bar;
console.log(foo.one);
console.log(foo.three);

62. console.log(foo.one);
bar
three: 3
foo
one: 1
two: 2
__proto__

63. console.log(foo.one);
bar
three: 3
foo
one: 1
two: 2
__proto__

64. console.log(foo.three);
bar
three: 3
foo
one: 1
two: 2
__proto__

65. console.log(foo.three);
bar
three: 3
foo
one: 1
two: 2
__proto__

66. console.log(foo.three);
bar
three: 3
foo
one: 1
two: 2
__proto__

67. End
Interm!zo

68. Behind the scenes...
var Person = function(name){
// this.prototype = {constructor: this}
var that = {};
that.name = name;
that.say = function(){
return "I am " + that.name;
};
return that;
};

69. Self invoking constructor
var Person = function(name){
if (this instanceof Person) {
this.name = name;
this.say = function(){
return "I am " + that.name;
}
}
else {
return new Person(name);
}
};
Person.prototype.iamhumanbeing = true;
var scott = new Person('Scott')
var adam = Person('Adam')
console.log(scott.name); // Scott
console.log(adam.name); // Adam
console.log(scott.iamhumanbeing); // true
console.log(adam.iamhumanbeing); // true
{pattern}

70. Self invoking constructor
var Person = function(name){
if (this instanceof Person) {
this.name = name;
this.say = function(){
return "I am " + that.name;
}
}
else {
return new Person(name);
}
};
Person.prototype.iamhumanbeing = true;
var scott = new Person('Scott')
var adam = Person('Adam')
console.log(scott.name); // Scott
console.log(adam.name); // Adam
console.log(scott.iamhumanbeing); // true
console.log(adam.iamhumanbeing); // true
{pattern}

71. Self invoking constructor
var Person = function(name){
if (this instanceof Person) {
this.name = name;
this.say = function(){
return "I am " + that.name;
}
}
else {
return new Person(name);
}
};
Person.prototype.iamhumanbeing = true;
var scott = new Person('Scott')
var adam = Person('Adam')
console.log(scott.name); // Scott
console.log(adam.name); // Adam
console.log(scott.iamhumanbeing); // true
console.log(adam.iamhumanbeing); // true
{pattern}

72. Self invoking constructor
var Person = function(name){
if (this instanceof Person) {
this.name = name;
this.say = function(){
return "I am " + that.name;
}
}
else {
return new Person(name);
}
};
Person.prototype.iamhumanbeing = true;
var scott = new Person('Scott')
var adam = Person('Adam')
console.log(scott.name); // Scott
console.log(adam.name); // Adam
console.log(scott.iamhumanbeing); // true
console.log(adam.iamhumanbeing); // true
{pattern}

73. Essential
Functions

74. Functions as first class objects

75. Immediate functions
(function(){
alert('watch out!');
})();

76. Initialization pattern
(function(){
var days = ['Sun', 'Mon', 'Tue', 'Wed',
'Thu', 'Fri', 'Sat'],
today = new Date(),
msg = 'Today is ' +
days[today.getDay()] +
', ' +
today.getDate();
console.log(msg);
})(); // "Today is Wed, 10"
{pattern}

77. Function scope

78. 5 globals...
// constructors
function Parent(){
}
function Child(){
}
// a variable
var some_var = 1;
// some objects
var module1 = {};
module1.data = {
a: 1,
b: 2
};
var module2 = {};
{antipattern}

79. 1 global!
// global object
var MYAPP = (function(){
{pattern}
var my = {};
// constructors
my.Parent = function(){};
my.Child = function(){};
// a variable
my.some_var = 1;
// an object container
my.modules = {};
// nested objects
my.modules.module1 = {};
my.modules.module1.data = {
a: 1,
b: 2
};
my.modules.module2 = {};
return my;
})();
console.log(MYAPP.modules.module1.data.a); // 1

80. 1 global!
// global object
var MYAPP = (function(){
{pattern}
var my = {};
// constructors
my.Parent = function(){};
my.Child = function(){};
// a variable
my.some_var = 1;
// an object container
my.modules = {};
// nested objects
my.modules.module1 = {};
my.modules.module1.data = {
a: 1,
b: 2
};
my.modules.module2 = {};
return my;
})();
console.log(MYAPP.modules.module1.data.a); // 1

81. What about encapsulation?

82. function Gadget(){
this.name = 'iPod';
this.stretch = function(){
return 'iPad';
}
};
var toy = new Gadget();
console.log(toy.name); // `iPod`
toy.name = 'Zune'
console.log(toy.name); // `Zune` is public
console.log(toy.stretch()); // stretch() is public
{antipattern}

83. Create private member
function Gadget(){
var name = 'iPod';
this.getName = function(){
return name;
}
};
var toy = new Gadget();
console.log(toy.getName()); // `iPod`
toy.name = 'Zune'
console.log(toy.getName()); // `iPod`
{pattern}

84. Create private member
function Gadget(){
var name = 'iPod';
this.getName = function(){
return name;
}
};
var toy = new Gadget();
console.log(toy.getName()); // `iPod`
toy.name = 'Zune'
console.log(toy.getName()); // `iPod`
{pattern}

85. Create private member
function Gadget(){
var name = 'iPod';
this.getName = function(){
return name;
}
};
var toy = new Gadget();
console.log(toy.getName()); // `iPod`
toy.name = 'Zune'
console.log(toy.getName()); // `iPod`
{pattern}

86. Create private member
function Gadget(){
var name = 'iPod';
this.getName = function(){
return name;
}
};
var toy = new Gadget();
console.log(toy.getName()); // `iPod`
toy.name = 'Zune'
console.log(toy.getName()); // `iPod`
{pattern}

87. for methods too
function Gadget() {
var name = 'iPod';
var upgrade = function(){
return 'iPhone';
}
this.getName = function () {
return name;
}
this.pay = function() {
return upgrade();
}
};
var toy = new Gadget();
console.log(toy.pay()); // `iPhone`
console.log(toy.upgrade()); // `error`
{pattern}

88. Advanced
Test Framework

89. JavaScript is madly in love with Testing.

90. JavaScript is madly in love with Testing.
JSUnit

91. JavaScript is madly in love with Testing.
JSUnit
JSTest

92. JavaScript is madly in love with Testing.
QUnit JSUnit
JSTest

93. JavaScript is madly in love with Testing.
QUnit JSUnit
Vows
JSTest

94. JavaScript is madly in love with Testing.
QUnit JSUnit
jsUnitTest Vows
JSTest

95. JavaScript is madly in love with Testing.
Blue Ridge
QUnit JSUnit
jsUnitTest Vows
JSTest

96. JavaScript is madly in love with Testing.
Screw unit Blue Ridge
QUnit JSUnit
jsUnitTest Vows
JSTest

97. JavaScript is madly in love with Testing.
Screw unit Blue Ridge
QUnit JSUnit
YUI Test
jsUnitTest Vows
JSTest

98. JavaScript is madly in love with Testing.
Screw unit Blue Ridge
JSpec
QUnit JSUnit
YUI Test
jsUnitTest Vows
JSTest

99. JavaScript is madly in love with Testing.
Screw unit Blue Ridge
JSpec
QUnit JSUnit
Unitesting
YUI Test
jsUnitTest Vows
JSTest

100. JavaScript is madly in love with Testing.
Screw unit Blue Ridge
JSpec
QUnit JSUnit
Unitesting Jasmine
YUI Test
jsUnitTest Vows
JSTest

101. JavaScript is madly in love with Testing.
http://pivotal.github.com/jasmine/

102. Jasmine: BDD RSpec-like syntax
describe('Array', function() {
var array;
describe('#unique', function() {
beforeEach(function() {
array = [3,3,4];
});
it("returns only the unique values in the array",
function() {
expect(array.unique()).toEqual([3,4]);
});
});
});

103. Not mocks and Stubs
Spies

104. Jasmine: Spies as Mocks
function BetterArray(array){
this.array = array;
}
BetterArray.prototype = {
joinify: function(){
// Does some cool stuff
this.array = this.array.join('.');
}
}

105. Jasmine: Spies as Mocks
describe('BetterArray', function() {
var betterArray, anArray = [3,3,4];
beforeEach(function() {
betterArray = new BetterArray(anArray);
});
describe('#joinify', function() {
it("calls the standard join method on Array",
function() {
var joinSpy = spyOn(betterArray.array, 'join');
betterArray.joinify();
expect(joinSpy).toHaveBeenCalled();
});
});
});

106. Jasmine: Spies as Mocks
describe('BetterArray', function() {
var betterArray, anArray = [3,3,4];
beforeEach(function() {
betterArray = new BetterArray(anArray);
});
describe('#joinify', function() {
it("calls the standard join method on Array",
function() {
var joinSpy = spyOn(betterArray.array, 'join');
betterArray.joinify();
expect(joinSpy).toHaveBeenCalled();
});
});
});

107. Jasmine: Spies as Mocks
describe('BetterArray', function() {
var betterArray, anArray = [3,3,4];
beforeEach(function() {
betterArray = new BetterArray(anArray);
});
describe('#joinify', function() {
it("calls the standard join method on Array",
function() {
var joinSpy = spyOn(betterArray.array, 'join');
betterArray.joinify();
expect(joinSpy).toHaveBeenCalled();
});
});
});

108. Jasmine: Spies as Mocks
describe('BetterArray', function() {
var betterArray, anArray = [3,3,4];
beforeEach(function() {
betterArray = new BetterArray(anArray);
});
describe('#joinify', function() {
it("calls the standard join method on Array",
function() {
var joinSpy = spyOn(betterArray.array, 'join');
betterArray.joinify();
expect(joinSpy).toHaveBeenCalled();
});
});
});

109. Advanced
Browser Patterns

110. JavaScript still live into browser...

111. Dom access: write
for (var i = 0; i < 100; i += 1) {
document.getElementById("result").innerHTML += i + ", ";
}
{antipattern}

112. Dom access: update local variable
var i, content = "";
for (i = 0; i < 100; i += 1) {
content += i + ",";
}
document.getElementById("result").innerHTML += content;
{pattern}

113. Dom access: read
var padding = document.getElementById("result").style.padding,
margin = document.getElementById("result").style.margin;
{antipattern}

114. Dom access: read with local variable
var style = document.getElementById("result").style,
padding = style.padding,
margin = style.margin;
{pattern}

115. Dom manipulation
// appending nodes as they are created
var p, t;
p = document.createElement('p');
t = document.createTextNode('first paragraph');
p.appendChild(t);
document.body.appendChild(p);
p = document.createElement('p');
t = document.createTextNode('second paragraph');
p.appendChild(t);
document.body.appendChild(p);
{antipattern}

116. Dom manipulation
// appending nodes as they are created
var p, t;
p = document.createElement('p');
t = document.createTextNode('first paragraph');
p.appendChild(t);
document.body.appendChild(p);
p = document.createElement('p');
t = document.createTextNode('second paragraph');
p.appendChild(t);
document.body.appendChild(p);
{antipattern}

117. Dom manipulation
var p, t, frag;
frag = document.createDocumentFragment();
p = document.createElement('p');
t = document.createTextNode('first paragraph');
p.appendChild(t);
frag.appendChild(p);
p = document.createElement('p');
t = document.createTextNode('second paragraph');
p.appendChild(t);
frag.appendChild(p);
document.body.appendChild(frag);
{pattern}

118. Dom manipulation
var p, t, frag;
frag = document.createDocumentFragment();
p = document.createElement('p');
t = document.createTextNode('first paragraph');
p.appendChild(t);
frag.appendChild(p);
p = document.createElement('p');
t = document.createTextNode('second paragraph');
p.appendChild(t);
frag.appendChild(p);
document.body.appendChild(frag);
{pattern}

119. Dom manipulation
var p, t, frag;
frag = document.createDocumentFragment();
p = document.createElement('p');
t = document.createTextNode('first paragraph');
p.appendChild(t);
frag.appendChild(p);
p = document.createElement('p');
t = document.createTextNode('second paragraph');
p.appendChild(t);
frag.appendChild(p);
document.body.appendChild(frag);
{pattern}

120. Dom manipulation
var p, t, frag;
frag = document.createDocumentFragment();
p = document.createElement('p');
t = document.createTextNode('first paragraph');
p.appendChild(t);
frag.appendChild(p);
p = document.createElement('p');
t = document.createTextNode('second paragraph');
p.appendChild(t);
frag.appendChild(p);
document.body.appendChild(frag);
{pattern}

121. The place of <script> element
<!doctype html>
<html>
<head>
<title>My App</title>
<script src="jquery.js"></script>
<script src="jquery.quickselect.js"></script>
<script src="jquery.lightbox.js"></script>
<script src="myapp.js"></script>
</head>
<body>
...
</body>
</html>
Worst
{antipattern}

122. The place of <script> element
<!doctype html>
<html>
<head>
<title>My App</title>
<script src="all_20110127.js"></script>
</head>
<body>
...
</body>
</html>
{antipattern}

123. The place of <script> element
<!doctype html>
<html>
<head>
<title>My App</title>
</head>
<body>
...
<script src="all_20110127.js"></script>
</body>
</html>
{pattern}

124. It’s just a beginning...

125. Study

127. “Save it for a rainy day!”

128. Check your code with jslint.com

131. http://jashkenas.github.com/coffee-script/

132. http://jashkenas.github.com/coffee-script/
It’s just JavaScript!

133. # Assignment: var cubes, math, num, number, opposite,
number = 42 race, square;
opposite = true var __slice = Array.prototype.slice;
number = 42;
opposite = true;
# Conditions: if (opposite) {
number = -42 if opposite number = -42;
}
# Functions: square = function(x) {
square = (x) -> x * x return x * x;
};
# Objects:
math = math = {
root: Math.sqrt root: Math.sqrt,
square: square square: square,
cube: (x) -> x * square x cube: function(x) {
return x * square(x);
}
};
race = function() {
# Splats: var runners, winner;
race = (winner, runners...) -> winner = arguments[0], runners = 2
print winner, runners <= arguments.length ?
__slice.call(arguments, 1) : [];
return print(winner, runners);
};}
JavaScript

134. # Assignment: var cubes, math, num, number, opposite,
number = 42 race, square;
opposite = true var __slice = Array.prototype.slice;
number = 42;
opposite = true;
# Conditions: if (opposite) {
number = -42 if opposite number = -42;
}
# Functions: square = function(x) {
square = (x) -> x * x return x * x;
};
# Objects:
math = math = {
root: Math.sqrt root: Math.sqrt,
square: square square: square,
cube: (x) -> x * square x cube: function(x) {
return x * square(x);
}
};
race = function() {
# Splats: var runners, winner;
race = (winner, runners...) -> winner = arguments[0], runners = 2
print winner, runners <= arguments.length ?
__slice.call(arguments, 1) : [];
return print(winner, runners);
};}
JavaScript

135. # Assignment: var cubes, math, num, number, opposite,
number = 42 race, square;
opposite = true var __slice = Array.prototype.slice;
number = 42;
opposite = true;
# Conditions: if (opposite) {
number = -42 if opposite number = -42;
}
# Functions: square = function(x) {
square = (x) -> x * x return x * x;
};
# Objects:
math = math = {
root: Math.sqrt root: Math.sqrt,
square: square square: square,
cube: (x) -> x * square x cube: function(x) {
return x * square(x);
}
};
race = function() {
# Splats: var runners, winner;
race = (winner, runners...) -> winner = arguments[0], runners = 2
print winner, runners <= arguments.length ?
__slice.call(arguments, 1) : [];
return print(winner, runners);
};}
JavaScript

136. # Assignment: var cubes, math, num, number, opposite,
number = 42 race, square;
opposite = true var __slice = Array.prototype.slice;
number = 42;
opposite = true;
# Conditions: if (opposite) {
number = -42 if opposite number = -42;
}
# Functions: square = function(x) {
square = (x) -> x * x return x * x;
};
# Objects:
math = math = {
root: Math.sqrt root: Math.sqrt,
square: square square: square,
cube: (x) -> x * square x cube: function(x) {
return x * square(x);
}
};
race = function() {
# Splats: var runners, winner;
race = (winner, runners...) -> winner = arguments[0], runners = 2
print winner, runners <= arguments.length ?
__slice.call(arguments, 1) : [];
return print(winner, runners);
};}
JavaScript

137. # Assignment: var cubes, math, num, number, opposite,
number = 42 race, square;
opposite = true var __slice = Array.prototype.slice;
number = 42;
opposite = true;
# Conditions: if (opposite) {
number = -42 if opposite number = -42;
}
# Functions: square = function(x) {
square = (x) -> x * x return x * x;
};
# Objects:
math = math = {
root: Math.sqrt root: Math.sqrt,
square: square square: square,
cube: (x) -> x * square x cube: function(x) {
return x * square(x);
}
};
race = function() {
# Splats: var runners, winner;
race = (winner, runners...) -> winner = arguments[0], runners = 2
print winner, runners <= arguments.length ?
__slice.call(arguments, 1) : [];
return print(winner, runners);
};}
JavaScript

138. # Assignment: var cubes, math, num, number, opposite,
number = 42 race, square;
opposite = true var __slice = Array.prototype.slice;
number = 42;
opposite = true;
# Conditions: if (opposite) {
number = -42 if opposite number = -42;
}
# Functions: square = function(x) {
square = (x) -> x * x return x * x;
};
# Objects:
math = math = {
root: Math.sqrt root: Math.sqrt,
square: square square: square,
cube: (x) -> x * square x cube: function(x) {
return x * square(x);
}
};
race = function() {
# Splats: var runners, winner;
race = (winner, runners...) -> winner = arguments[0], runners = 2
print winner, runners <= arguments.length ?
__slice.call(arguments, 1) : [];
return print(winner, runners);
};}
JavaScript

139. # Existence: if (typeof elvis != "undefined" && elvis !== null) {
alert "I knew it!" if elvis? alert("I knew it!");
}
# Array comprehensions: cubes = (function() {
cubes = (math.cube num for num in list) var _i, _len, _results;
_results = [];
for (_i = 0, _len = list.length; _i < _len; _i++) {
num = list[_i];
_results.push(math.cube(num));
}
return _results;
})();
JavaScript

140. # Existence: if (typeof elvis != "undefined" && elvis !== null) {
alert "I knew it!" if elvis? alert("I knew it!");
}
# Array comprehensions: cubes = (function() {
cubes = (math.cube num for num in list) var _i, _len, _results;
_results = [];
for (_i = 0, _len = list.length; _i < _len; _i++) {
num = list[_i];
_results.push(math.cube(num));
}
return _results;
})();
JavaScript

141. ...but it’s just another story...

143. giordano.scalzo@cleancode.it
@giordanoscalzo
www.slideshare.net/giordano
github.com/gscalzo
Roma,5 marzo 2011
http://creativecommons.org/licenses/by-nc-sa/3.0/