From 781af5047128127fb9fc6feebe444157b9b9cbf4 Mon Sep 17 00:00:00 2001
From: Elbert Alias <77259+AliasIO@users.noreply.github.com>
Date: Thu, 18 Jun 2020 14:51:38 +1000
Subject: [PATCH] Gracefully handle removed technologies

---
 src/drivers/webextension/js/driver.js | 34 +++++++++++++++------------
 src/wappalyzer.js                     | 22 +++++++++--------
 2 files changed, 31 insertions(+), 25 deletions(-)

diff --git a/src/drivers/webextension/js/driver.js b/src/drivers/webextension/js/driver.js
index 84713e98b..cb418f4b3 100644
--- a/src/drivers/webextension/js/driver.js
+++ b/src/drivers/webextension/js/driver.js
@@ -275,7 +275,9 @@ const Driver = {
     })
 
     // Remove duplicates
-    cache.detections = cache.detections.concat(detections)
+    cache.detections = cache.detections
+      .concat(detections)
+      .filter(({ technology }) => technology)
 
     cache.detections.filter(
       ({ technology: { name }, pattern: { regex } }, index) =>
@@ -309,20 +311,22 @@ const Driver = {
           ...cache,
           [hostname]: {
             ...Driver.cache.hostnames[hostname],
-            detections: Driver.cache.hostnames[hostname].detections.map(
-              ({
-                technology: { name: technology },
-                pattern: { regex, confidence },
-                version
-              }) => ({
-                technology,
-                pattern: {
-                  regex: regex.source,
-                  confidence
-                },
-                version
-              })
-            )
+            detections: Driver.cache.hostnames[hostname].detections
+              .filter(({ technology }) => technology)
+              .map(
+                ({
+                  technology: { name: technology },
+                  pattern: { regex, confidence },
+                  version
+                }) => ({
+                  technology,
+                  pattern: {
+                    regex: regex.source,
+                    confidence
+                  },
+                  version
+                })
+              )
           }
         }),
         {}
diff --git a/src/wappalyzer.js b/src/wappalyzer.js
index 250728995..d00fc8e1d 100644
--- a/src/wappalyzer.js
+++ b/src/wappalyzer.js
@@ -34,17 +34,19 @@ const Wappalyzer = {
         let version = ''
         let confidence = 0
 
-        detections.forEach(
-          ({ technology: { name }, pattern, version: _version = '' }) => {
-            if (name === technology.name) {
-              confidence = Math.min(100, confidence + pattern.confidence)
-              version =
-                _version.length > version.length && _version.length <= 10
-                  ? _version
-                  : version
+        detections
+          .filter(({ technology }) => technology)
+          .forEach(
+            ({ technology: { name }, pattern, version: _version = '' }) => {
+              if (name === technology.name) {
+                confidence = Math.min(100, confidence + pattern.confidence)
+                version =
+                  _version.length > version.length && _version.length <= 10
+                    ? _version
+                    : version
+              }
             }
-          }
-        )
+          )
 
         resolved.push({ technology, confidence, version })
       }