Add stdin

Author: Ffloriel

rollup.config.js

@@ -17,6 +17,6 @@ export default {
         }
     ],
     plugins: [builtins(), resolve(), flow(), commonjs(), babel()],
-    external: ["postcss", "postcss-selector-parser"],
+    external: ["postcss", "postcss-selector-parser", "fs"],
     sourceMap: false
 }

src/index.js

@@ -74,6 +74,7 @@ class Purgecss {
         // Get css selectors and remove unused ones
         let files = []
         for (let file of this.options.css) {
+            const cssContent = this.options.stdin ? file : fs.readFileSync(file, 'utf8')
             files.push({
                 file,
                 css: this.getSelectorsCss(cssContent, cssClasses)