## CoffeeScript

### by Daniel Pimentel — Tue 06 June 2006

CoffeeScript is a little language that compiles into
JavaScript. Underneath that awkward Java-esque patina, JavaScript has
always had a gorgeous heart. CoffeeScript is an attempt to expose the
good parts of JavaScript in a simple way.

#### Emacs

```
# Assignment:
number = 42
opposite = true
# Conditions:
number = -42 if opposite
# Functions:
square = (x) -> x * x
# Arrays:
list = [1, 2, 3, 4, 5]
# Objects:
math =
root: Math.sqrt
square: square
cube: (x) -> x * square x
# Splats:
race = (winner, runners...) ->
print winner, runners
# Existence:
alert "I knew it!" if elvis?
# Array comprehensions:
cubes = (math.cube num for num in list)
var cubes, list, math, num, number, opposite, race, square,
slice = [].slice;
number = 42;
opposite = true;
if (opposite) {
number = -42;
}
square = function(x) {
return x * x;
};
list = [1, 2, 3, 4, 5];
math = {
root: Math.sqrt,
square: square,
cube: function(x) {
return x * square(x);
}
};
race = function() {
var runners, winner;
winner = arguments[0], runners = 2 <= arguments.length ? slice.call(arguments, 1) : [];
return print(winner, runners);
};
if (typeof elvis !== "undefined" && elvis !== null) {
alert("I knew it!");
}
cubes = (function() {
var i, len, results;
results = [];
for (i = 0, len = list.length; i < len; i++) {
num = list[i];
results.push(math.cube(num));
}
return results;
})();
```

CoffeeScript