feat: add ability to pass options to postcss plugins (#176)

* add ability to pass options to postcss plugins

* add postcss plugin options usage docs into readme

Author: gbiryukov

README.md

@@ -208,7 +208,7 @@ Missing a configuration? [Raise an issue](https://github.com/gajus/babel-plugin-
 ```js
 type FiletypeOptionsType = {|
   +syntax: string,
-  +plugins?: $ReadOnlyArray<string>
+  +plugins?: $ReadOnlyArray<string | $ReadOnlyArray<[string, mixed]>>
 |};
 
 type FiletypesConfigurationType = {
@@ -251,11 +251,25 @@ To add support for different CSS syntaxes (e.g. SCSS), perform the following two
   "filetypes": {
     ".scss": {
       "syntax": "postcss-scss",
-      "plugins": ["postcss-nested"]
+      "plugins": [
+        "postcss-nested"
+      ]
     }
   }
   ```
-
+  
+  Postcss plugins can have options specified by wrapping the name and an options object in an array inside your config
+  
+  ```json
+    "plugins": [
+      ["postcss-import-sync2", {
+        "path": ["src/styles", "shared/styles"]
+      }],
+      "postcss-nested"
+    ]
+  ```  
+   
+  
 ### Custom Attribute Mapping
 
 You can set your own attribute mapping rules using the `attributeNames` option.

src/requireCssModule.js

@@ -21,7 +21,7 @@ import type {
 
 type FiletypeOptionsType = {|
   +syntax: string,
-  +plugins?: $ReadOnlyArray<string>
+  +plugins?: $ReadOnlyArray<string | $ReadOnlyArray<[string, mixed]>>
 |};
 
 type FiletypesConfigurationType = {
@@ -52,6 +52,13 @@ const getExtraPlugins = (filetypeOptions: ?FiletypeOptionsType): $ReadOnlyArray<
   }
 
   return filetypeOptions.plugins.map((plugin) => {
+    if (Array.isArray(plugin)) {
+      const [pluginName, pluginOptions] = plugin;
+
+      // eslint-disable-next-line import/no-dynamic-require, global-require
+      return require(pluginName)(pluginOptions);
+    }
+
     // eslint-disable-next-line import/no-dynamic-require, global-require
     return require(plugin);
   });

src/schemas/optionsSchema.json

@@ -15,7 +15,14 @@
           "properties": {
             "plugins": {
               "items": {
-                "type": "string"
+                "oneOf": [
+                  {
+                    "type": "string"
+                  },
+                  {
+                    "type": "array"
+                  }
+                ]
               },
               "type": "array"
             },