Pre validate multiple attributes thedersen#303

Author: Luiz Américo

src/backbone-validation.js

@@ -206,20 +206,26 @@ Backbone.Validation = (function(_){
         preValidate: function(attr, value) {
           var self = this,
               result = {},
-              error;
+              error,
+              allAttrs = _.extend({}, this.attributes);
 
           if(_.isObject(attr)){
-            _.each(attr, function(value, key) {
-              error = self.preValidate(key, value);
+            // if multiple attributes are passed at once we would like for the validation functions to
+            // have access to the fresh values sent for all attributes, in the same way they do in the
+            // regular validation
+            _.extend(allAttrs, attr);
+
+            _.each(attr, _.bind(function(value, attrKey) {
+              error = validateAttr(this, attrKey, value, allAttrs);
               if(error){
-                result[key] = error;
+                result[attrKey] = error;
               }
-            });
+            }, this));
 
             return _.isEmpty(result) ? undefined : result;
           }
           else {
-            return validateAttr(this, attr, value, _.extend({}, this.attributes));
+            return validateAttr(this, attr, value, allAttrs);
           }
         },
 

test/preValidate.js

@@ -68,7 +68,50 @@ module.exports = {
           refute(this.model.preValidate({ name: 'name' }));
         }
       }
-    }
-  }
+    },
+
+    "when model has dependancies between validation functions": {
+        setUp: function() {
+          var CARD_TYPES = {
+            VISA : 0,
+            AMEX : 1
+          };
+          var Model = Backbone.Model.extend({
+            validation: {
+              card_type: {
+                required: true
+              },
+              security_code: function(value, attr, computedState){
+                var requiredLength = (computedState.card_type === CARD_TYPES.AMEX? 4 : 3);
+                if(value && _.isString(value) && value.length !== requiredLength) {
+                  return 'Please enter a valid security code.';
+                }
+              }
+            }
+          });
+          Model.CARD_TYPES = CARD_TYPES;
+          this.ModelDefinition = Model;
+          this.model = new Model();
+          Backbone.Validation.bind(new Backbone.View({model: this.model}));
+        },
+
+        "and pre-validating hash of attributes": {
+          "returns error object when value is not valid": function() {
+            var result = this.model.preValidate({card_type: this.ModelDefinition.CARD_TYPES.VISA, security_code: '1234'});
+            assert(result.security_code);
+            refute(result.card_type);
+          },
 
+          "returns error object when values are not valid": function() {
+            var result = this.model.preValidate({card_type: '', security_code: '12345'});
+            assert(result.card_type);
+            assert(result.security_code);
+          },
+
+          "returns nothing when value is valid": function() {
+            refute(this.model.preValidate({card_type: this.ModelDefinition.CARD_TYPES.AMEX, security_code: '1234'}));
+          }
+        }
+      }
+    }
 }