diff --git a/modules/io.mjs b/modules/io.mjs
index 227b22188..f038c889f 100644
--- a/modules/io.mjs
+++ b/modules/io.mjs
@@ -3549,6 +3549,11 @@ function readMapElement(buf) {
    }
 
    const n = buf.ntoi4(), res = new Array(n);
+
+   // no extra data written for empty map
+   if (n === 0)
+      return res;
+
    if (this.member_wise && (buf.remain() >= 6)) {
       if (buf.ntoi2() === kStreamedMemberWise)
          buf.shift(4); // skip checksum