Added an example and a test to pass options to PostCSS

Author: w0rm

README.md

@@ -30,6 +30,26 @@ gulp.task('css', function () {
 });
 ```
 
+## Passing additional options to PostCSS
+
+The second optional argument to gulp-postcss is passed to PostCSS.
+
+This, for instance, may be used to enable custom syntax:
+
+```js
+var gulp = require('gulp');
+var postcss = require('gulp-postcss');
+var nested = require('postcss-nested');
+var scss = require('postcss-scss');
+
+gulp.task('default', function () {
+    var processors = [nested];
+    return gulp.src('in.css')
+        .pipe(postcss(processors, {syntax: scss}))
+        .pipe(gulp.dest('out'));
+});
+```
+
 ## Using a custom processor
 
 ```js
@@ -74,6 +94,9 @@ return gulp.src('./src/*.css')
 
 ## Changelog
 
+* 6.0.1
+  * Added an example and a test to pass options to PostCSS (e.g. `syntax` option)
+
 * 6.0.0
   * Updated PostCSS to version 5.0.0
 

test.js

@@ -245,6 +245,40 @@ describe('PostCSS Guidelines', function () {
 
   })
 
+  it('should pass options down to PostCSS', function (cb) {
+
+    var customSyntax = function () {}
+    var options = {
+      syntax: customSyntax
+    }
+
+    var stream = postcss([ doubler ], options)
+    var cssPath = __dirname + '/src/fixture.css'
+    postcssStub.process.returns(Promise.resolve({
+      css: ''
+    , warnings: function () {
+        return []
+      }
+    }))
+
+    stream.on('data', function () {
+      var resultOptions = postcssStub.process.getCall(0).args[1]
+      // remove automatically set options
+      delete resultOptions.from
+      delete resultOptions.to
+      delete resultOptions.map
+      assert.deepEqual(resultOptions, options)
+      cb()
+    })
+
+    stream.write(new gutil.File({
+      contents: new Buffer('a {}')
+    , path: cssPath
+    }))
+
+    stream.end()
+
+  })
 
 })