diff --git a/src/core/BufferAttribute.js b/src/core/BufferAttribute.js
index aed5087bcf4a0a40e8b7a9a3bda26ead59587f04..e6c950c53869e48b971773e3d6e45972a961de88 100644
--- a/src/core/BufferAttribute.js
+++ b/src/core/BufferAttribute.js
@@ -32,7 +32,7 @@ function BufferAttribute( array, itemSize, normalized ) {
 
 }
 
-BufferAttribute.prototype = {
+Object.assign( BufferAttribute.prototype, {
 
 	constructor: BufferAttribute,
 
@@ -335,7 +335,7 @@ BufferAttribute.prototype = {
 
 	}
 
-};
+} );
 
 //