Return error in request

lib/store.js

@@ -5,12 +5,23 @@ var store;
 var adapter;
 var Report;
 
+function error(msg) {
+  return new Promise(function(resolve, reject) {
+    return resolve({ error: msg });
+  });
+}
+
 function add(data) {
+  if (!data.type || !data.payload) {
+    return error('Required parameters aren\'t specified.');
+  }
+  
   var obj = {
     id: uuid.v4(),
     type: data.type,
     payload: data.payload
   };
+
   if (!adapter) {
     return new Promise(function(resolve) {
       var report = Report.inject(obj);