diff --git a/src/drivers/npm/driver.js b/src/drivers/npm/driver.js
index 2ff328d06..c4a4c5b8c 100644
--- a/src/drivers/npm/driver.js
+++ b/src/drivers/npm/driver.js
@@ -1145,7 +1145,7 @@ class Site {
             patterns[name].push({
               type,
               regex: regex.source,
-              value: value.length <= 250 ? value : null,
+              value: String(value).length <= 250 ? value : null,
               match: match.length <= 250 ? match : null,
               confidence,
               version,