diff --git a/index.js b/index.js
index 4a57ffc..395036e 100644
--- a/index.js
+++ b/index.js
@@ -35,10 +35,10 @@ function hasBinary (obj) {
     return false;
   }
 
-  if ((global.Buffer && global.Buffer.isBuffer && global.Buffer.isBuffer(obj)) ||
-     (global.ArrayBuffer && obj instanceof ArrayBuffer) ||
-     (global.Blob && obj instanceof Blob) ||
-     (global.File && obj instanceof File)
+  if ((typeof global.Buffer === 'function' && global.Buffer.isBuffer && global.Buffer.isBuffer(obj)) ||
+     (typeof global.ArrayBuffer === 'function' && obj instanceof ArrayBuffer) ||
+     (typeof global.Blob === 'function' && obj instanceof Blob) ||
+     (typeof global.File === 'function' && obj instanceof File)
     ) {
     return true;
   }
diff --git a/test.js b/test.js
index bbe12f1..8e65ff3 100644
--- a/test.js
+++ b/test.js
@@ -73,5 +73,10 @@ describe('has-binarydata', function () {
     it('should work with a Blob', function () {
       assert(hasBinary(new Blob()));
     });
+  } else {
+    it('should not crash if global Blob is not a function', function () {
+      global.Blob = [ 1, 2, 3 ];
+      assert(!hasBinary(global.Blob));
+    });
   }
 });