check for data property

lib/common/util.js

@@ -245,9 +245,7 @@ function getType(value) {
  */
 function prop(name) {
   return function(item) {
-    if (name in item) {
-      return item[name];
-    }
+    return item[name];
   };
 }
 

lib/pubsub/topic.js

@@ -134,7 +134,7 @@ Topic.prototype.autoCreateWrapper_ = function(method, path, q, body, callback) {
  * messageIds is returned in the response.
  *
  * @throws {Error} If no message is provided.
- * @throws {Error} If a message is not an object.
+ * @throws {Error} If a message is missing a data property.
  *
  * @param {object|object[]} message - The message(s) to publish.
  * @param {*} message.data - The contents of the message.
@@ -179,11 +179,9 @@ Topic.prototype.publish = function(messages, callback) {
     throw new Error('Cannot publish without a message.');
   }
 
-  messages.forEach(function(message) {
-    if (!util.is(message, 'object')) {
-      throw new Error('Cannot publish message:\n\t' + JSON.stringify(message));
-    }
-  });
+  if (!messages.every(util.prop('data'))) {
+    throw new Error('Cannot publish message without a `data` property.');
+  }
 
   callback = callback || util.noop;
 

test/pubsub/topic.js

@@ -129,17 +129,17 @@ describe('Topic', function() {
     it('should throw if no message is provided', function() {
       assert.throws(function() {
         topic.publish();
-      }, /Cannot publish/);
+      }, /Cannot publish without a message/);
 
       assert.throws(function() {
         topic.publish([]);
-      }, /Cannot publish/);
+      }, /Cannot publish without a message/);
     });
 
-    it('should throw if a message is not an object', function() {
+    it('should throw if a message has no data', function() {
       assert.throws(function() {
         topic.publish(message);
-      }, /Cannot publish message/);
+      }, /Cannot publish message without a `data` property/);
     });
 
     it('should send correct api request', function(done) {