Merge pull request #975 from stephenplusplus/spp--datastore-get-examples

datastore: docs: show example of updating an entity

lib/datastore/request.js

@@ -151,6 +151,19 @@ function DatastoreRequest() {}
  *   .on('end', function() {
  *     // All entities retrieved.
  *   });
+ *
+ * //-
+ * // Here's how you would update the value of an entity with the help of the
+ * // `save` method.
+ * //-
+ * dataset.get(key, function(err, entity) {
+ *   if (err) {
+ *     // Error handling omitted.
+ *   }
+ *
+ *   entity.data.newValue = true;
+ *   dataset.save(entity, function(err) {});
+ * });
  */
 DatastoreRequest.prototype.get = function(keys, callback) {
   if (is.fn(callback)) {