Allow re-ordering of the plugins array via config

README.md

@@ -118,6 +118,42 @@ module.exports = {
 npm run preprocess
 ```
 
+#### Changing plugin order
+
+If duplicate plugins are used, `suitcss` will remove duplicates but also respect the new order. This is useful if you need to change the default order:
+
+```js
+// Default order
+var defaults = [
+  'postcss-import',
+  'postcss-custom-properties',
+  'postcss-calc',
+  'postcss-custom-media',
+  'autoprefixer',
+  'postcss-reporter'
+];
+
+// config
+module.exports = {
+  use: [
+    'stylelint',
+    'postcss-calc',
+    'autoprefixer',
+    'postcss-reporter'
+  ]
+};
+
+var result = [
+  'postcss-import',
+  'postcss-custom-properties',
+  'postcss-custom-media',
+  'stylelint',
+  'postcss-calc',
+  'autoprefixer',
+  'postcss-reporter'
+];
+```
+
 ### Node.js
 
 Returns a [PostCSS promise](https://github.com/postcss/postcss/blob/master/docs/api.md#lazyresult-class)

lib/index.js

@@ -2,8 +2,8 @@
  * Module dependencies
  */
 var assign = require('object-assign-deep');
-var without = require('lodash/array/without');
-var last = require('lodash/array/last');
+var isEmpty = require('lodash.isempty');
+var difference = require('lodash.difference');
 var autoprefixer = require('autoprefixer');
 var bemLinter = require('postcss-bem-linter');
 var postcss = require('postcss');
@@ -104,11 +104,11 @@ function mergeOptions(options) {
   merged['postcss-import'].root = options.root;
   merged['postcss-import'].transform = lintImportedFiles(merged);
 
-  // Ensure postcss-reporter is always the final plugin
-  if (last(merged.use) !== 'postcss-reporter') {
-    var plugins = without(merged.use, 'postcss-reporter');
-    plugins.push('postcss-reporter');
-    merged.use = plugins;
+  // Allow additional plugins to be merged with the defaults
+  // but remove any duplicates so that it respects the new order
+  if (!isEmpty(options.config.use)) {
+    var dedupedPlugins = difference(merged.use, options.config.use);
+    merged.use = dedupedPlugins.concat(options.config.use);
   }
 
   return merged;

package.json

@@ -15,9 +15,10 @@
     "chokidar": "^1.3.0",
     "colors": "~1.1.2",
     "commander": "~2.9.0",
-    "fs-extra": "^0.26.2",
     "cssnano": "^3.3.2",
-    "lodash": "^3.10.1",
+    "fs-extra": "^0.26.2",
+    "lodash.difference": "^3.2.2",
+    "lodash.isempty": "^3.0.4",
     "object-assign-deep": "0.0.4",
     "pad-component": "0.0.1",
     "postcss": "^5.0.12",

test/test.js

@@ -24,11 +24,12 @@ describe('suitcss', function () {
     expect(function() {suitcss({});}).to.throw(Error);
   });
 
-  describe('passing options', function() {
+  describe('using options', function() {
     var mergeOptions, defaults;
 
     beforeEach(function() {
       mergeOptions = suitcss.__get__('mergeOptions');
+      defaults = suitcss.__get__('defaults');
     });
 
     it('should use default options when nothing is passed', function() {
@@ -41,6 +42,8 @@ describe('suitcss', function () {
       ];
       expect(mergeOptions({})).to.have.keys(keys);
       expect(mergeOptions()).to.have.keys(keys);
+      expect(mergeOptions({}).use).to.eql(defaults.use);
+      expect(mergeOptions().use).to.eql(defaults.use);
     });
 
     it('should allow an import root to be set', function() {
@@ -58,7 +61,6 @@ describe('suitcss', function () {
       var opts = mergeOptions({
         root: 'test/root',
         config: {
-          use: ['postcss-property-lookup'],
           autoprefixer: autoprefixer
         }
       });
@@ -69,12 +71,50 @@ describe('suitcss', function () {
         'postcss-calc',
         'postcss-custom-media',
         'autoprefixer',
-        'postcss-property-lookup',
         'postcss-reporter'
       ]);
       expect(opts.autoprefixer).to.eql(autoprefixer);
       expect(opts['postcss-import'].root).to.equal('test/root');
     });
+
+    describe('re-ordering plugins', function() {
+      it('should allow reordering of use array and remove duplicates', function() {
+        var opts = mergeOptions({
+          config: {
+            use: ['autoprefixer', 'postcss-at2x', 'postcss-calc', 'postcss-reporter']
+          }
+        });
+
+        expect(opts.use).to.eql([
+          'postcss-import',
+          'postcss-custom-properties',
+          'postcss-custom-media',
+          'autoprefixer',
+          'postcss-at2x',
+          'postcss-calc',
+          'postcss-reporter'
+        ]);
+      });
+
+      it('should just append plugins if no duplicates are used', function() {
+        var opts = mergeOptions({
+          config: {
+            use: ['postcss-at2x', 'postcss-property-lookup']
+          }
+        });
+
+        expect(opts.use).to.eql([
+          'postcss-import',
+          'postcss-custom-properties',
+          'postcss-calc',
+          'postcss-custom-media',
+          'autoprefixer',
+          'postcss-reporter',
+          'postcss-at2x',
+          'postcss-property-lookup'
+        ]);
+      });
+    });
   });
 });