Added testing option to force use untyped arrays

lib/zlib/utils.js

@@ -1,5 +1,23 @@
 'use strict';
 
+
+var TYPED_OK =  (typeof Uint8Array !== 'undefined') &&
+                (typeof Uint16Array !== 'undefined') &&
+                (typeof Uint32Array !== 'undefined');
+
+var _toString = Function.prototype.call.bind(Object.prototype.toString);
+var isArray = Array.isArray || function (obj) { return _toString(obj) === '[object Array]'; };
+
+// For debug/testing. Set true to force use untyped arrays
+exports.forceUntyped = false;
+
+function typedOk() {
+  return TYPED_OK && !exports.forceUntyped;
+}
+
+exports.typedOk = typedOk;
+
+
 exports.assign = function (obj /*from1, from2, from3, ...*/) {
   var sources = Array.prototype.slice.call(arguments, 1);
   while (sources.length) {
@@ -25,8 +43,7 @@ exports.arraySet = function (dest, src, src_offs, len, dest_offs) {
 
   // Suppose, that with typed array support destination is
   // always typed - don't check it
-  if ((typeof Uint8Array !== 'undefined') &&
-      (!Array.isArray(src))) {
+  if (typedOk() && (!isArray(src))) {
 
     // optimize full copy
     //if ((src_offs === 0) && (src.length === len)) {
@@ -47,7 +64,7 @@ exports.arraySet = function (dest, src, src_offs, len, dest_offs) {
 
 exports.arrayCreate = function (length) {
 
-  if ((typeof Uint8Array !== 'undefined')) {
+  if (typedOk()) {
     return new Uint8Array(length);
   }
 
@@ -58,7 +75,7 @@ exports.arrayCreate = function (length) {
 
 exports.array16Create = function (length) {
 
-  if ((typeof Uint16Array !== 'undefined')) {
+  if (typedOk()) {
     return new Uint16Array(length);
   }
 
@@ -72,5 +89,6 @@ exports.fill = function (buf, val) {
 
   if (!len) { return;}
 
+  // fastest for untyped Array
   while (--len) { buf[len] = val; }
 };