linter-coffee-variables 
This is a plugin for Linter that does some things that CoffeeLint can't: detecting variables that are used without being defined, and defined variables that aren't used.
It's best used in conjunction with linter-coffeelint.
Behind the scenes it works by compiling your CoffeeScript to JavaScript and running it through ESLint, using specific rules.
Installation
- Install Linter
$ apm install linter-coffee-variables