By far, the most common question people new to CoffeeSccript seem to have is, ‘How do I do a for loop?’
How Do You Write a For Loop in CoffeeScript?
In CoffeeScript, loops are expressed as comprehensions. This is a feature of the language, as you can express complicated loops in a single line of code, or in a very terse syntax.
The down side is, conventional for and while loops don’t really translate easily into CoffeeScript for people looking for a straight syntax port.
js2coffee.org To the Rescue