diff --git a/src/drivers/npm/driver.js b/src/drivers/npm/driver.js
index cbf828d52..de45d7727 100644
--- a/src/drivers/npm/driver.js
+++ b/src/drivers/npm/driver.js
@@ -67,11 +67,16 @@ function getJs(page, technologies = Wappalyzer.technologies) {
           const value = chain
             .split('.')
             .reduce(
-              (value, method) => (value ? value[method] : undefined),
+              (value, method) =>
+                value &&
+                value instanceof Object &&
+                Object.prototype.hasOwnProperty.call(value, method)
+                  ? value[method]
+                  : '__UNDEFINED__',
               window
             )
 
-          if (typeof value !== 'undefined') {
+          if (value !== '__UNDEFINED__') {
             technologies.push({
               name,
               chain,
diff --git a/src/drivers/webextension/js/inject.js b/src/drivers/webextension/js/inject.js
index 63d81ec45..c554dccfb 100644
--- a/src/drivers/webextension/js/inject.js
+++ b/src/drivers/webextension/js/inject.js
@@ -14,7 +14,7 @@
       postMessage({
         wappalyzer: {
           js: technologies.reduce((technologies, { name, chains }) => {
-            chains.forEach((chain) => {
+            chains.forEach((chain, index) => {
               const value = chain
                 .split('.')
                 .reduce(
@@ -23,11 +23,11 @@
                     value instanceof Object &&
                     Object.prototype.hasOwnProperty.call(value, method)
                       ? value[method]
-                      : undefined,
+                      : '__UNDEFINED__',
                   window
                 )
 
-              if (value !== undefined) {
+              if (value !== '__UNDEFINED__') {
                 technologies.push({
                   name,
                   chain,