eyeglass is a node-sass (github) extension manager built on top of npm. Using eyeglass, you can bring the power of node modules to your Sass files.

# for programatic functionality
npm install eyeglass --save-dev

eyeglass modules are regular npm modules. Install them into your project just like any other item.

npm install my_eyeglass_module --save-dev

Once installed via npm, an eyeglass module can:

• Provide stylesheets that you can import with special node_module syntax.
• Add additional custom functions to Sass that are written in javascript.

In Sass files, you can reference the eyeglass module with standard Sass import syntax: @import "my_eyeglass_module/file";. The my_eyeglass_module will be resolved to the correct directory in your node modules, and the file will then resolve using the standard import rules for Sass.

To create an eyeglass module with Sass files, place the files inside of a sass directory in your npm module.

|- /
  |- eyeglass-exports.js
  |- package.json
  |- sass
    |- index.scss (or .sass)

eyeglass will automatically map the first directory of @import statements to the correct node-module directory if there is a eyeglass module with that eyeglass name. Because Sass uses a global namespace, it's recommended that you namespace-prefix any mixins you create in order to avoid collisions.

In keeping with node's conventions, eyeglass modules can create an index.scss file in any folder instead of defining a file of the same name as a folder in order to be the main entry point for a sass module having submodules.

The easiest way to use eyeglass is to use an eyeglass-aware build-tool plugin. The following plugins are available:

• broccoli-eyeglass
• ember-cli-eyeglass

Eyeglass is designed to be easy to use with any node-sass based compilation system.

var Eyeglass = require("eyeglass");
var sass = require("node-sass")
var sassOptions = { ... } ; // options for node-sass
var eyeglass = new Eyeglass(sassOptions);

// futher configuration of the eyeglass instance can happen here.

// Expose images in the assets/images directory as /images on the
// website by putting the images we reference with asset-url()
// into the public/images directory.
eyeglass.assets("assets/images", "images", "public/images");

// Expose fonts in the assets/fonts directory as /fonts on the
// website by putting the fonts we reference with asset-url()
// into the public/fonts directory.
eyeglass.assets("assets/fonts", "fonts", "public/fonts");

// These options can be passed to any sass build tool that passes
// options through to node-sass.
sass.render(eyeglass.sassOptions(), function(error, result) {
  if (error) {
    //handle the compilation error
  } else {
    // write the result.css output to a file.
  }
});

...
sass: {
    options: require("eyeglass")({
        sourceMap: true
    }).sassOptions(),
    dist: {
        files: {
            'public/css/main.css': 'sass/main.scss'
        }
    }
}
...

• Assets integration
• Per-css callback for import-once support.
• etc.

node-sass allows you to register custom functions for advanced functionality. Eyeglass allows any node modules that are tagged with eyeglass-module to be automatically loaded into eyeglass. To tag your module as an eyeglass module, add the eyeglass-module keyword to your package.json

{
  ...
  "keywords": ["eyeglass-module", "sass", ...],
  "main": "eyeglass-exports.js",
  ...
}

Your requirable module exports an object that describes your module's structure and can expose javascript functions as sass functions. Below is an example eyeglass exports file:

"use strict";

var path = require("path");

module.exports = function(eyeglass, sass) {
  return {
    sassDir: path.join(__dirname, "sass"),
    functions: {
      "hello($name: 'World')": function(name, done) {
        done(sass.types.String("Hello, " + name.getValue()));
      }
    }
  }
};

If your package.json main file is already in use for something else, you can still export eyeglass functions by specifying eyeglass: 'path/to/eyeglass-exports.js' or by specifying an eyeglass object with an exports attribute:

{
  ...
  "main": "lib/my-awesome-main-file.js",
  "eyeglass": {
    "exports": "lib/eyeglass-exports.js"
  }
  ...
}

If you need the top level import to be named differently than the name of your npm module (this is not best practice) then you can specify a name attribute for the eyeglass object in your package.json. The following example would allow @import "foo"; to import index.scss from your package's sass directory.

{
  ...
  "name": "eyeglass-foo",
  "eyeglass": {
    "name": "foo"
  }
  ...
}

Any sass files imported from your node modules will only ever be imported once per CSS output file. Note that Sass files imported from the Sass load path will have the standard Sass @import behavior.