FullHuman · Ffloriel · Jan 5, 2018 · Dec 31, 2017 · Dec 31, 2017
diff --git a/README.md b/README.md
@@ -77,6 +77,13 @@ new PurgecssPlugin({
 })
 ```
 
+If you want to regenerate the paths list on every compilation (e.g. with `--watch`), then you can also pass a function:
+```js
+new PurgecssPlugin({
+  paths: () => glob.sync(`${PATHS.src}/*`)
+})
+```
+
 * #### only
 
 You can specify entrypoints to the purgecss-webpack-plugin with the option only:
@@ -88,6 +95,27 @@ new PurgecssPlugin({
 })
 ```
 
+* #### whitelist and whitelistPatterns
+
+Similar as for the `paths` option, you also can define functions for the these options:
+
+```js
+function collectWhitelist() {
+    // do something to collect the whitelist
+    return ['whitelisted'];
+}
+function collectWhitelistPatterns() {
+    // do something to collect the whitelist
+    return [/^whitelisted-/];
+}
+
+// In the webpack configuration
+new PurgecssPlugin({
+  whitelist: collectWhitelist,
+  whitelistPatterns: collectWhitelistPatterns
+})
+```
+
 ## Contributing
 
 Please read [CONTRIBUTING.md](./.github/CONTRIBUTING.md) for details on our code of conduct, and the process for submitting pull requests to us.

diff --git a/__tests__/__snapshots__/webpack-integration.test.js.snap b/__tests__/__snapshots__/webpack-integration.test.js.snap
@@ -1,5 +1,20 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`Webpack Integration Tests path-and-whitelist-functions 1`] = `
+".hello {
+  color: red;
+}
+
+.whitelisted {
+  color: green;
+}
+
+md\\\\:w-2\\\\/3 {
+  color: red;
+}
+"
+`;
+
 exports[`Webpack Integration Tests simple 1`] = `
 ".hello {
   color: red;

diff --git a/__tests__/cases/path-and-whitelist-functions/expected/style.css b/__tests__/cases/path-and-whitelist-functions/expected/style.css
@@ -0,0 +1,11 @@
+.hello {
+  color: red;
+}
+
+.whitelisted {
+  color: green;
+}
+
+md\:w-2\/3 {
+  color: red;
+}
diff --git a/__tests__/cases/path-and-whitelist-functions/src/content.html b/__tests__/cases/path-and-whitelist-functions/src/content.html
@@ -0,0 +1,13 @@
+<html>
+
+<head>
+  <title>Purgecss webpack test</title>
+</head>
+
+<body>
+  <div class="md:w-2/3"></div>
+  <div class="hello"></div>
+  <div></div>
+</body>
+
+</html>
diff --git a/__tests__/cases/path-and-whitelist-functions/src/index.js b/__tests__/cases/path-and-whitelist-functions/src/index.js
@@ -0,0 +1 @@
+import './../style.css'
diff --git a/__tests__/cases/path-and-whitelist-functions/style.css b/__tests__/cases/path-and-whitelist-functions/style.css
@@ -0,0 +1,15 @@
+.hello {
+  color: red;
+}
+
+.unused {
+  color: blue;
+}
+
+.whitelisted {
+  color: green;
+}
+
+md\:w-2\/3 {
+  color: red;
+}
diff --git a/__tests__/cases/path-and-whitelist-functions/webpack.config.js b/__tests__/cases/path-and-whitelist-functions/webpack.config.js
@@ -0,0 +1,41 @@
+const path = require('path')
+const glob = require('glob')
+const ExtractTextPlugin = require('extract-text-webpack-plugin')
+const PurgecssPlugin = require('../../../src/').default
+
+class CustomExtractor {
+  static extract(content) {
+    return content.match(/[A-z0-9-:/]+/g)
+  }
+}
+
+const PATHS = {
+  src: path.join(__dirname, 'src')
+}
+
+module.exports = {
+  entry: './src/index.js',
+  module: {
+    rules: [
+      {
+        test: /\.css$/,
+        use: ExtractTextPlugin.extract({
+          use: 'css-loader?sourceMap'
+        })
+      }
+    ]
+  },
+  plugins: [
+    new ExtractTextPlugin('style.css'),
+    new PurgecssPlugin({
+      paths: () => glob.sync(`${PATHS.src}/*`),
+      whitelist: () => ['whitelisted'],
+      extractors: [
+        {
+          extractor: CustomExtractor,
+          extensions: ['html', 'js']
+        }
+      ]
+    })
+  ]
+}
diff --git a/src/index.js b/src/index.js
@@ -55,12 +55,19 @@ export default class PurgecssPlugin {
 
             // Compile through Purgecss and attach to output.
             // This loses sourcemaps should there be any!
-            const purgecss = new Purgecss({
+            const options = {
               ...this.options,
               content: filesToSearch,
               css: [asset.source()],
               stdin: true
-            })
+            };
+            if (typeof options.whitelist === 'function') {
+              options.whitelist = options.whitelist();
+            }
+            if (typeof options.whitelistPatterns === 'function') {
+              options.whitelistPatterns = options.whitelistPatterns();
+            }
+            const purgecss = new Purgecss(options);
             compilation.assets[name] = new ConcatSource(purgecss.purge()[0].css)
           })
         })

diff --git a/src/parse.js b/src/parse.js
@@ -1,9 +1,13 @@
 export const entryPaths = paths => {
-    const ret = paths || []
+    let ret = paths || []
+
+    if (typeof ret === 'function') {
+        ret = ret();
+    }
 
     // Convert possible string to an array
     if (typeof ret === 'string') {
-        return [ret]
+        ret = [ret]
     }
 
     return ret