diff --git a/source/import/importer.js b/source/import/importer.js
index 1cfb89b..3d7ea41 100644
--- a/source/import/importer.js
+++ b/source/import/importer.js
@@ -34,42 +34,41 @@ OV.ImportResult = class
     }
 };
 
-OV.ImportBuffers = class
+OV.ImporterFileAccessor = class
 {
     constructor (getBufferCallback)
     {
         this.getBufferCallback = getBufferCallback;
-        this.fileBuffers = {};
-        this.textureBuffers = {};
+        this.fileBuffers = new Map ();
+        this.textureBuffers = new Map ();
     }
 
     GetFileBuffer (filePath)
     {
         let fileName = OV.GetFileName (filePath);
-        let buffer = this.fileBuffers[fileName];
-        if (buffer === undefined) {
-            buffer = this.getBufferCallback (fileName);
-            this.fileBuffers[fileName] = buffer;
+        if (this.fileBuffers.has (fileName)) {
+            return this.fileBuffers.get (fileName);
         }
+        let buffer = this.getBufferCallback (fileName);
+        this.fileBuffers.set (fileName, buffer);
         return buffer;
     }
 
     GetTextureBuffer (filePath)
     {
         let fileName = OV.GetFileName (filePath);
-        let buffer = this.textureBuffers[fileName];
-        if (buffer === undefined) {
-            let textureBuffer = this.getBufferCallback (fileName);
-            if (textureBuffer !== null) {
-                buffer = {
-                    url : OV.CreateObjectUrl (textureBuffer),
-                    buffer : textureBuffer
-                };
-            } else {
-                buffer = null;
-            }
-            this.textureBuffers[fileName] = buffer;
+        if (this.textureBuffers.has (fileName)) {
+            return this.textureBuffers.get (fileName);
         }
+        let buffer = null;
+        let textureBuffer = this.getBufferCallback (fileName);
+        if (textureBuffer !== null) {
+            buffer = {
+                url : OV.CreateObjectUrl (textureBuffer),
+                buffer : textureBuffer
+            };
+        }
+        this.textureBuffers.set (fileName, buffer);
         return buffer;
     }
 };
@@ -176,7 +175,7 @@ OV.Importer = class
         this.usedFiles.push (mainFile.file.name);
 
         let importer = mainFile.importer;
-        let buffers = new OV.ImportBuffers ((fileName) => {
+        let fileAccessor = new OV.ImporterFileAccessor ((fileName) => {
             let fileBuffer = null;
             let file = this.fileList.FindFileByPath (fileName);
             if (file === null || file.content === null) {
@@ -196,10 +195,10 @@ OV.Importer = class
                 return material;
             },
             getFileBuffer : (filePath) => {
-                return buffers.GetFileBuffer (filePath);
+                return fileAccessor.GetFileBuffer (filePath);
             },
             getTextureBuffer : (filePath) => {
-                return buffers.GetTextureBuffer (filePath);
+                return fileAccessor.GetTextureBuffer (filePath);
             },
             onSuccess : () => {
                 let result = new OV.ImportResult ();
diff --git a/test/utils/testfiles.js b/test/utils/testfiles.js
index 5709025..6daa6d0 100644
--- a/test/utils/testfiles.js
+++ b/test/utils/testfiles.js
@@ -3,43 +3,43 @@ var testUtils = require ('./testutils.js');
 module.exports =
 {
     ImportObjFile : function (fileName, onReady)
-    {    
+    {
         var importer = new OV.ImporterObj ();
         this.ImportFile (importer, 'obj', fileName, onReady);
     },
 
     ImportStlFile : function (fileName, onReady)
-    {    
+    {
         var importer = new OV.ImporterStl ();
         this.ImportFile (importer, 'stl', fileName, onReady);
     },
 
     ImportOffFile : function (fileName, onReady)
-    {    
+    {
         var importer = new OV.ImporterOff ();
         this.ImportFile (importer, 'off', fileName, onReady);
     },
 
     ImportPlyFile : function (fileName, onReady)
-    {    
+    {
         var importer = new OV.ImporterPly ();
         this.ImportFile (importer, 'ply', fileName, onReady);
     },
 
     Import3dsFile : function (fileName, onReady)
-    {    
+    {
         var importer = new OV.Importer3ds ();
         this.ImportFile (importer, '3ds', fileName, onReady);
     },
 
     ImportGltfFile : function (folderName, fileName, onReady)
-    {    
+    {
         var importer = new OV.ImporterGltf ();
         this.ImportFile (importer, 'gltf/' + folderName, fileName, onReady);
     },
 
     ImportO3dvFile : function (fileName, onReady)
-    {    
+    {
         var importer = new OV.ImporterO3dv ();
         this.ImportFile (importer, 'o3dv', fileName, onReady);
     },
@@ -48,7 +48,7 @@ module.exports =
     {
         let content = testUtils.GetArrayBufferFileContent (folder, fileName);
         var extension = OV.GetFileExtension (fileName);
-        let buffers = new OV.ImportBuffers (function (filePath) {
+        let fileAccessor = new OV.ImporterFileAccessor (function (filePath) {
             let fileContent = testUtils.GetArrayBufferFileContent (folder, filePath);
             return fileContent;
         });
@@ -58,10 +58,10 @@ module.exports =
                 return material;
             },
             getFileBuffer : function (filePath) {
-                return buffers.GetFileBuffer (filePath);
+                return fileAccessor.GetFileBuffer (filePath);
             },
             getTextureBuffer : function (filePath) {
-                return buffers.GetTextureBuffer (filePath);
+                return fileAccessor.GetTextureBuffer (filePath);
             },
             onSuccess : function () {
                 let model = importer.GetModel ();
@@ -71,7 +71,7 @@ module.exports =
                 onReady (model);
             },
             onComplete : function () {
-                
+
             }
         });
     }