diff --git a/src/loaders/WWOBJLoader2.js b/src/loaders/WWOBJLoader2.js
index 7d9b3e3b..3f192f95 100644
--- a/src/loaders/WWOBJLoader2.js
+++ b/src/loaders/WWOBJLoader2.js
@@ -203,7 +203,7 @@ THREE.OBJLoader2.WWOBJLoader2 = (function () {
 		if ( this.dataAvailable ) {
 
 			// fast-fail on bad type
-			if ( ! params.objAsArrayBuffer instanceof Uint8Array ) {
+			if ( ! ( params.objAsArrayBuffer instanceof Uint8Array ) ) {
 				throw 'Provided input is not of type arraybuffer! Aborting...';
 			}