Adding a method to find validation errors by path

lib/errors.js

@@ -30,12 +30,45 @@ error.BaseError.prototype = Object.create(Error.prototype, {
  *
  * @constructor
  */
-error.ValidationError = function() {
+error.ValidationError = function(message, errors) {
   error.BaseError.apply(this, arguments);
   this.name = 'SequelizeValidationError';
+  this.errors = errors || [];
 
   return this;
 };
 error.ValidationError.prototype = Object.create(error.BaseError.prototype, {
   constructor: { value: error.ValidationError }
 });
+
+/**
+ * Finds all validation error items for the path specified.
+ *
+ * @param {string} path The path to be checked for error items
+ * @returns {Array} Validation error items for the specified path
+ */
+error.ValidationError.prototype.errorsForPath = function(path) {
+  return this.errors.reduce(function(reduced, error) {
+    if (error.path === path) {
+      reduced.push(error);
+    }
+    return reduced;
+  }, []);
+};
+
+/**
+ * Validation Error Item
+ * Instances of this class are included in the ValidationError errors property.
+ *
+ * @param {string} message An error message
+ * @param {string} type The type of the validation error
+ * @param {string} path The field that triggered the validation error
+ * @param {string} value The value that generated the error
+ * @constructor
+ */
+error.ValidationErrorItem = function(message, type, path, value) {
+  this.message = message || '';
+  this.type = type || null;
+  this.path = path || null;
+  this.value = value || null;
+};
\ No newline at end of file

test/error.test.js

@@ -30,6 +30,20 @@ describe(Support.getTestDialectTeaser("Sequelize Errors"), function () {
       expect(validationError).to.have.property('name', 'SequelizeValidationError');
       expect(instError).to.be.instanceOf(Sequelize.Error);
       expect(instValidationError).to.be.instanceOf(Sequelize.ValidationError);
-    })
+    });
+    it('SequelizeValidationError should find errors by path', function() {
+      var errorItems = [
+        new Sequelize.ValidationErrorItem('invalid', 'type', 'first_name', null),
+        new Sequelize.ValidationErrorItem('invalid', 'type', 'last_name', null)
+      ];
+      var validationError = new Sequelize.ValidationError('Validation error', errorItems);
+      expect(validationError).to.have.property('errorsForPath');
+      expect(validationError.errorsForPath).to.be.a('function');
+
+      var matches = validationError.errorsForPath('first_name');
+      expect(matches).to.be.instanceOf(Array);
+      expect(matches).to.have.lengthOf(1);
+      expect(matches[0]).to.have.property('message', 'invalid')
+    });
   })
 });