Whew, see, I extract the following phrases from  CoffeeScript PDF book.

No matter what level you’re at, be sure to do the exercises at the end of each
chapter. They’re designed to be quick yet challenging, illustrating some of
the most common pitfalls CoffeeScripters fall into.

How do you share data between modules?
The answer is you attach them to an existing global variable. One option is
to use the root object, which is the only object whose properties can be ref-
erenced without qualification. In a browser environment, the root object is
window. In Node, it’s global.

A prototype is an object whose properties are shared by all objects that have
that prototype. An object’s prototype can usually be accessed using the
aptly-named prototype property, though there are exceptions.2
However, you can’t just go and write A.prototype = B. Instead, you need to use
the new keyword, which takes a function called a constructor and creates
an object that “inherits” the constructor’s prototype.