diff --git a/compiler/jsgen.nim b/compiler/jsgen.nim
index 3a1ef7fbb8..675a24c923 100644
--- a/compiler/jsgen.nim
+++ b/compiler/jsgen.nim
@@ -2598,14 +2598,6 @@ proc genHeader(): Rope =
     var framePtr = null;
     var excHandler = 0;
     var lastJSError = null;
-    if (typeof Int8Array === 'undefined') Int8Array = Array;
-    if (typeof Int16Array === 'undefined') Int16Array = Array;
-    if (typeof Int32Array === 'undefined') Int32Array = Array;
-    if (typeof Uint8Array === 'undefined') Uint8Array = Array;
-    if (typeof Uint16Array === 'undefined') Uint16Array = Array;
-    if (typeof Uint32Array === 'undefined') Uint32Array = Array;
-    if (typeof Float32Array === 'undefined') Float32Array = Array;
-    if (typeof Float64Array === 'undefined') Float64Array = Array;
   """.unindent.format(VersionAsString))
 
 proc addHcrInitGuards(p: PProc, n: PNode,