diff --git a/lib/server/parse-http.js b/lib/server/parse-http.js
index 24c3c69..bf6cb2c 100644
--- a/lib/server/parse-http.js
+++ b/lib/server/parse-http.js
@@ -25,7 +25,7 @@ function parseHttpRequest (req, opts) {
     if (!params.port) throw new Error('invalid port')
 
     params.left = Number(params.left)
-    if (isNaN(params.left)) params.left = Infinity
+    if (Number.isNaN(params.left)) params.left = Infinity
 
     params.compact = Number(params.compact) || 0
     params.numwant = Math.min(