Introduce plugins option

Author: Jed Mao

README.md

@@ -100,6 +100,13 @@ Default: `null`
 
 A function to transform the content of imported files. Take one argument (file content) & should return the modified content.
 
+#### `plugins`
+
+Type: `Array`
+Default: `undefined`
+
+An array of plugins you wish you apply on each imported file.
+
 #### `encoding`
 
 Type: `String`  

index.js

@@ -83,7 +83,8 @@ function AtImport(options) {
       importedFiles,
       ignoredAtRules,
       null,
-      hashFiles
+      hashFiles,
+      createProcessor(result, options.plugins)
     ).then(function() {
       addIgnoredAtRulesOnTop(styles, ignoredAtRules)
 
@@ -94,6 +95,16 @@ function AtImport(options) {
   }
 }
 
+function createProcessor(result, plugins) {
+  if (plugins) {
+    if (Array.isArray(plugins)) {
+      return postcss(plugins)
+    }
+    result.warn("plugins must be an array")
+  }
+  return postcss()
+}
+
 /**
  * lookup for @import rules
  *
@@ -107,7 +118,8 @@ function parseStyles(
   importedFiles,
   ignoredAtRules,
   media,
-  hashFiles
+  hashFiles,
+  processor
 ) {
   var imports = []
   styles.eachAtRule("import", function checkAtRule(atRule) {
@@ -130,7 +142,8 @@ function parseStyles(
         importedFiles,
         ignoredAtRules,
         media,
-        hashFiles
+        hashFiles,
+        processor
       )
     }, atRule.source)
   }))
@@ -225,7 +238,8 @@ function readAtImport(
   importedFiles,
   ignoredAtRules,
   media,
-  hashFiles
+  hashFiles,
+  processor
 ) {
   // parse-import module parse entire line
   // @todo extract what can be interesting from this one
@@ -283,7 +297,8 @@ function readAtImport(
     importedFiles,
     ignoredAtRules,
     media,
-    hashFiles
+    hashFiles,
+    processor
   )
 }
 
@@ -304,7 +319,8 @@ function readImportedContent(
   importedFiles,
   ignoredAtRules,
   media,
-  hashFiles
+  hashFiles,
+  processor
 ) {
   // add directory containing the @imported file in the paths
   // to allow local import from this file
@@ -357,10 +373,20 @@ function readImportedContent(
     importedFiles,
     ignoredAtRules,
     parsedAtImport.media,
-    hashFiles
-  ).then(function() {
-    insertRules(atRule, parsedAtImport, newStyles, resolvedFilename)
-  })
+    hashFiles,
+    processor
+  )
+    .then(function() {
+      return processor.process(newStyles)
+        .then(function(newResult) {
+          newResult.warnings().forEach(function(message) {
+            result.warn(message)
+          })
+        })
+    })
+    .then(function() {
+      insertRules(atRule, parsedAtImport, newStyles)
+    })
 }
 
 /**

package.json

@@ -34,6 +34,8 @@
   "devDependencies": {
     "css-whitespace": "^1.1.0",
     "eslint": "^0.23.0",
+    "postcss-bem-linter": "^0.3.0",
+    "postcss-nested": "^0.3.2",
     "tape": "^3.0.0"
   },
   "scripts": {

test/fixtures/imports/block-bar.css

@@ -0,0 +1,13 @@
+/** @define block-bar */
+
+.block-bar {
+  color: green;
+
+  &--modifier {
+    color: yellow;
+  }
+
+  &__element {
+    color: black;
+  }
+}

test/fixtures/imports/block-foo.css

@@ -0,0 +1,13 @@
+/** @define block-foo */
+
+.block-foo {
+  color: red;
+
+  &--modifier {
+    color: white;
+  }
+
+  &__element {
+    color: blue;
+  }
+}

test/fixtures/plugins.css

@@ -0,0 +1,2 @@
+@import block-foo;
+@import block-bar;

test/fixtures/plugins.expected.css

@@ -0,0 +1,26 @@
+/** @define block-foo */
+
+.block-foo {
+  color: red;
+}
+
+.block-foo--modifier {
+  color: white;
+}
+
+.block-foo__element {
+  color: blue;
+}
+/** @define block-bar */
+
+.block-bar {
+  color: green;
+}
+
+.block-bar--modifier {
+  color: yellow;
+}
+
+.block-bar__element {
+  color: black;
+}

test/index.js

@@ -1,5 +1,6 @@
 var test = require("tape")
 
+var assign = require("object-assign")
 var path = require("path")
 var fs = require("fs")
 
@@ -16,9 +17,8 @@ function read(name) {
 }
 
 function compareFixtures(t, name, msg, opts, postcssOpts) {
-  opts = opts || {path: importsDir}
-  postcss()
-    .use(atImport(opts))
+  opts = assign({path: importsDir}, opts || {})
+  postcss(atImport(opts))
     .process(read("fixtures/" + name), postcssOpts)
     .then(trimResultCss)
     .then(function(actual) {
@@ -42,28 +42,33 @@ test("@import", function(t) {
 
   compareFixtures(t, "glob", "should handle a glob pattern", {
     root: __dirname,
-    path: importsDir,
     glob: true,
   })
 
   compareFixtures(
     t,
     "glob-alt",
      "should handle a glob pattern with single quote and/or url(...)", {
-    path: importsDir,
-    glob: true,
-  })
+      glob: true,
+    })
+
   compareFixtures(t, "recursive", "should import stylsheets recursively")
 
   compareFixtures(t, "relative", "should import stylsheets relatively")
 
   compareFixtures(t, "empty-and-useless", "should work with empty files")
 
   compareFixtures(t, "transform", "should support transform", {
-    path: importsDir,
     transform: require("css-whitespace"),
   })
 
+  compareFixtures(t, "plugins", "should support plugins", {
+    plugins: [
+      require("postcss-nested"),
+      require("postcss-bem-linter"),
+    ],
+  })
+
   compareFixtures(t, "cwd", "should work without a specified path", {})
 
   compareFixtures(
@@ -78,7 +83,7 @@ test("@import", function(t) {
     t,
     "modules",
     "should be able to consume npm package or local modules",
-    {root: __dirname, path: importsDir}
+    {root: __dirname}
   )
 
   var base = "@import url(http://)"