Fix type validations being to strict for dates (#6453)

* Fix type validations being to strict for dates

* Add changelog entry

changelog.md

+# Future
+- [FIXED] Accept dates as string while using `typeValidation` [#6453](https://github.com/sequelize/sequelize/issues/6453)
+
 # 3.24.1
 # 3.24.1
 - [FIXED] Add `parent`, `original` and `sql` properties to `UniqueConstraintError`
 - [FIXED] Add `parent`, `original` and `sql` properties to `UniqueConstraintError`
 
 

lib/data-types.js

@@ -458,7 +458,7 @@ DATE.prototype.toSql = function() {
   return 'DATETIME';
   return 'DATETIME';
 };
 };
 DATE.prototype.validate = function(value) {
 DATE.prototype.validate = function(value) {
-  if (!_.isDate(value)) {
+  if (!Validator.isDate(String(value))) {
     throw new sequelizeErrors.ValidationError(util.format('%j is not a valid date', value));
     throw new sequelizeErrors.ValidationError(util.format('%j is not a valid date', value));
   }
   }
 
 

test/unit/model/validation.test.js

@@ -274,7 +274,8 @@ describe(Support.getTestDialectTeaser('InstanceValidator'), function() {
       name: Sequelize.STRING,
       name: Sequelize.STRING,
       awesome: Sequelize.BOOLEAN,
       awesome: Sequelize.BOOLEAN,
       number: Sequelize.DECIMAL,
       number: Sequelize.DECIMAL,
-      uid: Sequelize.UUID
+      uid: Sequelize.UUID,
+      date: Sequelize.DATE
     });
     });
 
 
     before(function () {
     before(function () {
@@ -303,6 +304,14 @@ describe(Support.getTestDialectTeaser('InstanceValidator'), function() {
           })).not.to.be.rejected;
           })).not.to.be.rejected;
         });
         });
 
 
+        it('should allow dates as a string', function() {
+          return expect(User.find({
+            where: {
+              date: '2000-12-16'
+            }
+          })).not.to.be.rejected;
+        });
+
         it('should allow decimal big numbers as a string', function () {
         it('should allow decimal big numbers as a string', function () {
           return expect(User.create({
           return expect(User.create({
             number: '2321312301230128391820831289123012'
             number: '2321312301230128391820831289123012'