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CoffeeScript is a little language that compiles into JavaScript. It provides a simple syntax without lots of braces and parentheses. The code compiles one-to-one into the equivalent JS, and there is no interpretation at runtime.

CoffeeScript is supported on both the client and the server. Files ending with .coffee, .litcoffee, or are automatically compiled to JavaScript.

Namespacing and CoffeeScript

Here's how CoffeeScript works with Meteor's namespacing.

  • Per the usual CoffeeScript convention, CoffeeScript variables are file-scoped by default (visible only in the .coffee file where they are defined.)

  • When writing a package, CoffeeScript-defined variables can be exported like any other variable (see Writing Packages). Exporting a variable pulls it up to package scope, meaning that it will be visible to all of the code in your app or package (both .js and .coffee files).

  • Package-scope variables declared in .js files are visible in any .coffee files in the same app or project.

  • There is no way to make a package-scope variable from a .coffee file other than exporting it. We couldn't figure out a way to make this fit naturally inside the CoffeeScript language. If you want to use package-scope variables with CoffeeScript, one way is to make a short .js file that declares all of your package-scope variables. They can then be read, mutated, and extended in .coffee files.

  • If you want to share variables between .coffee files in the same package, and don't want to separately declare them in a .js file, we have an experimental feature that you may like. An object called share is visible in CoffeeScript code and is shared across all .coffee files in the same package. So, you can write for a value that is shared between all CoffeeScript code in a package, but doesn't escape that package.

Modules and CoffeeScript

See Modules » CoffeeScript Syntax.

Testing This Package

Follow the instructions to check out the Meteor repo and run test-packages. Once you can do that successfully, to test the coffeescript package run:

./meteor test-packages packages/non-core/coffeescript