diff --git a/AUTHORS b/AUTHORS
index 5416f8dec17d8..7e42decb1d5f3 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -590,4 +590,5 @@ a license to everyone to use it as detailed in LICENSE.)
 * Alexander Vestin <alex.vestin@gmail.com>
 * Xiaobing Yang <yangxiaobing@jwzg.com>
 * Alexandra Cherdantseva <neluhus.vagus@gmail.com>
-* Skye Gibney <skyejgibney@gmail.com>
\ No newline at end of file
+* Michael Schmuki <michael@schmuki.io>
+* Skye Gibney <skyejgibney@gmail.com>
diff --git a/src/library_pthread.js b/src/library_pthread.js
index 77f9ce794bb7d..d6866c7aaefec 100644
--- a/src/library_pthread.js
+++ b/src/library_pthread.js
@@ -648,8 +648,9 @@ var LibraryPThread = {
 
     var offscreenCanvases = {}; // Dictionary of OffscreenCanvas objects we'll transfer to the created thread to own
     var moduleCanvasId = Module['canvas'] ? Module['canvas'].id : '';
-    for (var name of transferredCanvasNames) {
-      name = name.trim();
+    // Note that transferredCanvasNames might be null (so we cannot do a for-of loop).  
+    for (var i in transferredCanvasNames) {
+      var name = transferredCanvasNames[i].trim();
       var offscreenCanvasInfo;
       try {
         if (name == '#canvas') {