diff --git a/plugin/npm-module/monitor.js b/plugin/npm-module/monitor.js
index 360085e..e813741 100644
--- a/plugin/npm-module/monitor.js
+++ b/plugin/npm-module/monitor.js
@@ -31,6 +31,7 @@ module.exports = class MonitorStats {
         .map(chunk => chunk.files)
         .reduce((arr, el) => arr.concat(el))
         .filter(file => /\.js($|\?)/.test(file))
+        .filter(file => compilation.assets[file])
         .forEach((file) => {
           const source = compilation.assets[file].source();
           const minified = source.split(/\r\n|\r|\n/).length < 25;
@@ -45,12 +46,13 @@ module.exports = class MonitorStats {
       cb();
     });
 
-    // // CHECK UNPURE CSS
+    // CHECK UNPURE CSS
     compiler.plugin('emit', (compilation, cb) => {
       const css = compilation.chunks
         .map(chunk => chunk.files)
         .reduce((arr, el) => arr.concat(el))
         .filter(file => /\.css($|\?)/.test(file))
+        .filter(file => compilation.assets[file])
         .reduce((concat, file) => {
           const sourceCSS = compilation.assets[file].source();
           return concat += sourceCSS;
@@ -60,24 +62,30 @@ module.exports = class MonitorStats {
         .map(chunk => chunk.files)
         .reduce((arr, el) => arr.concat(el))
         .filter(file => /\.js($|\?)/.test(file))
+        .filter(file => compilation.assets[file])
         .reduce((concat, file) => {
           const sourceJs = compilation.assets[file].source();
           return concat += sourceJs;
         }, '');
 
-      const purified = purifycss(js, css, { minify: false });
+      const purified = purifycss(js || '', css || '', { minify: false });
       pureSize = purified.length;
       cb();
     });
 
     // CHECK IF TARGET DIRECTORY EXISTS...
-    if (!fs.existsSync(target)) {
+    const targetDir = path.dirname(target)
+    if (!fs.existsSync(targetDir)) {
       // ...make directory if it does not
-      fs.mkdirSync(path.resolve(__dirname, '../..', 'monitor'));
-      data = [];
-    } else {
+      fs.mkdirSync(targetDir);
+    }
+    
+    // CHECK IF TARGET FILE EXISTS...
+    if (fs.existsSync(target)) {
       // ...get existing data if it does
       data = JSON.parse(fs.readFileSync(target, { encoding: 'utf8' }));
+    } else {
+      data = [];
     }
 
     compiler.plugin('done', (stats) => {