I have used CoffeeScript for a while. Now I need to write a npm package, can I write it in CoffeeScript, or I should compile CoffeeScript into JavaScript?
I have written npm packages in CoffeeScript from scratch. I encourage you to use CoffeScript for node as well as for the Browser. However, before you can use or publish your module, you have to compile the source CoffeeScript to JavaScript. That should not hold you back from using CoffeeScript, though.
Tip: While developing, use coffee -cw yourfile.coffee (command line) to watch the file for changes and compile on save.