added possibility to skip queries once a query failed

lib/query-chainer.js

@@ -37,29 +37,44 @@ module.exports = (function() {
     return this.eventEmitter.run()
   }
 
-  QueryChainer.prototype.runSerial = function() {
-    var self   = this
+  QueryChainer.prototype.runSerial = function(options) {
+    var self = this
+
+    options = Utils._.extend({
+      skipOnError: false
+    }, options)
 
     var exec = function() {
       var serial = self.serials.pop()
 
       if(serial) {
-        var emitter = serial.klass[serial.method].apply(serial.klass, serial.params)
-        emitter.success(function() {
-          if(serial.options && serial.options.success) {
-            serial.options.success(serial.klass, function() {
-              self.finishedEmits++
-              exec()
-            })
-          } else {
-            self.finishedEmits++
-            exec()
-          }
-        }).error(function(err) {
+        serial.options = serial.options || {}
+        serial.options.before && serial.options.before(serial.klass)
+
+        var onSuccess = function() {
+          serial.options.after && serial.options.after(serial.klass)
+          self.finishedEmits++
+          exec()
+        }
+
+        var onError = function(err) {
+          serial.options.after && serial.options.after(serial.klass)
           self.finishedEmits++
           self.fails.push(err)
           exec()
-        })
+        }
+
+        if(options.skipOnError && (self.fails.length > 0)) {
+          onError('Skipped due to earlier error!')
+        } else {
+          var emitter = serial.klass[serial.method].apply(serial.klass, serial.params)
+          emitter.success(function() {
+            if(serial.options.success)
+              serial.options.success(serial.klass, onSuccess)
+            else
+              onSuccess()
+          }).error(onError)
+        }
       } else {
         self.wasRunning = true
         finish.call(self)