Add user configurable PostCSS plugins.

Author: joshgillies

README.md

@@ -1,6 +1,8 @@
 # css-modulesify
 
-A browserify transform to load [CSS Modules](https://github.com/css-modules/css-modules).
+A browserify transform to load [CSS Modules].
+
+[CSS Modules]: https://github.com/css-modules/css-modules
 
 **Please note that this is still highly experimental.**
 
@@ -27,6 +29,35 @@ var div = `<div class="${styles.inner}">...</div>`;
 
 The generated css will contain locally-scoped versions of any css you have `require`'d, and will be written out to the file you specify in the `--output` or `-o` option.
 
+### PostCSS Plugins
+
+The following PostCSS plugins are enabled by default:
+
+  * [postcss-modules-local-by-default]
+  * [postcss-modules-extract-imports]
+  * [postcss-modules-scope]
+
+(i.e. the [CSS Modules] specification).
+
+You can supply your own additional PostCSS Plugins by passing `--use|-u` to `css-modulesify`.
+
+In addion you may also wish to configure defined PostCSS plugins by passing `--plugin.option true`.
+
+An example of this would be:
+
+```
+browserify -p [css-modulesify -u postcss-modules-local-by-default \
+  -u postcss-modules-extract-imports \
+  -u postcss-modules-scope \
+  -u postcss-color-rebeccapurple \
+  -u autoprefixer --autoprefixer.browsers '> 5%' \
+  -o dist/main.css] -o dist/index.js src/index.js
+```
+
+[postcss-modules-local-by-default]: https://github.com/css-modules/postcss-modules-local-by-default
+[postcss-modules-extract-imports]: https://github.com/css-modules/postcss-modules-extract-imports
+[postcss-modules-scope]: https://github.com/css-modules/postcss-modules-scope
+
 ## Example
 
 An example implementation can be found [here](https://github.com/css-modules/browserify-demo).

index.js

@@ -1,6 +1,7 @@
 var fs = require('fs');
 var path = require('path');
 var through = require('through');
+var Core = require('css-modules-loader-core');
 var FileSystemLoader = require('css-modules-loader-core/lib/file-system-loader');
 var assign = require('object-assign');
 
@@ -13,6 +14,33 @@ module.exports = function (browserify, options) {
     throw new Error('css-modulesify needs the --output / -o option (path to output css file)');
   }
 
+  // PostCSS plugins passed to FileSystemLoader
+  var plugins = options.use || options.u;
+  if (!plugins) {
+    plugins = Core.defaultPlugins;
+  } else {
+    if (typeof plugins === 'string') {
+      plugins = [ plugins ];
+    }
+
+    plugins = plugins.map(function requirePlugin (name) {
+      // assume objects are already required plugins
+      if (typeof name === 'object') {
+        return name;
+      }
+
+      var plugin = require(name);
+
+      if (name in options) {
+        plugin = plugin(options[name]);
+      } else {
+        plugin = plugin.postcss || plugin();
+      }
+
+      return plugin;
+    });
+  }
+
   // keep track of css files visited
   var filenames = [];
 
@@ -36,7 +64,7 @@ module.exports = function (browserify, options) {
     return through(function noop () {}, function end () {
       var self = this;
 
-      var loader = new FileSystemLoader(path.dirname(filename));
+      var loader = new FileSystemLoader(path.dirname(filename), plugins);
 
       // pre-populate the loader's tokensByFile
       loader.tokensByFile = tokensByFile;