diff --git a/README.md b/README.md
index c4da8e814..9291bfd23 100644
--- a/README.md
+++ b/README.md
@@ -6306,7 +6306,6 @@ const isDuplexStream = val =>
val !== null &&
typeof val === 'object' &&
typeof val.pipe === 'function' &&
- typeof val.pipe === 'function' &&
typeof val._read === 'function' &&
typeof val._readableState === 'object' &&
typeof val._write === 'function' &&
diff --git a/docs/node.html b/docs/node.html
index 90f1f3c1e..0edb294d5 100644
--- a/docs/node.html
+++ b/docs/node.html
@@ -141,7 +141,6 @@ console.log<
val !== null &&
typeof val === 'object' &&
typeof val.pipe === 'function' &&
- typeof val.pipe === 'function' &&
typeof val._read === 'function' &&
typeof val._readableState === 'object' &&
typeof val._write === 'function' &&