stream: remove useless check

diff --git a/lib/_stream_readable.js b/lib/_stream_readable.js
index fd63969..1d486cf 100755 (executable)
--- a/lib/_stream_readable.js
+++ b/lib/_stream_readable.js
@@ -360,8 +360,7 @@ function chunkInvalid(state, chunk) {
       'string' !== typeof chunk &&
       chunk !== null &&
       chunk !== undefined &&
-      !state.objectMode &&
-      !er) {
+      !state.objectMode) {
     er = new TypeError('Invalid non-string/buffer chunk');
   }
   return er;