add present validation

Author: Mark

src/Validations/index.js

@@ -1541,6 +1541,30 @@ Validations.nullable = function (data, field, message, args, validations) {
   });
 };
 
+/**
+ * @description Validate the value must exist
+ * values
+ * @method nullable
+ * @param  {Object} data
+ * @param  {String} field
+ * @param  {String} message
+ * @param  {Array} args
+ * @param  {Array} validations
+ * @return {Boolean}
+ * @public
+ */
+Validations.present = function (data, field, message, args, validations) {
+  return new Promise(function (resolve, reject) {
+    const fieldValue = _.get(data, field);
+
+    if (typeof fieldValue !== 'undefined') {
+      resolve('validation passed');
+    }
+
+    reject(message);
+  });
+};
+
 /**
  * aliases
  */

test/validations.spec.js

@@ -2909,4 +2909,38 @@ describe('Validations', function () {
 
   });
 
+  describe('Present', function () {
+    it('should work fine when field value is exist', function *() {
+      const data = { username: 'DDD' };
+      const field = 'username';
+      const message = 'Username should be present';
+      const args = [];
+      const passes = yield Validations.present(data, field, message, args);
+      expect(passes).to.equal('validation passed');
+    });
+
+    it('should work fine when field value is null', function *() {
+      const data = { username: null };
+      const field = 'username';
+      const message = 'Username should be present';
+      const args = [];
+      const passes = yield Validations.present(data, field, message, args);
+      expect(passes).to.equal('validation passed');
+    });
+
+    it('should throw an error when the field value is a undefined', function *() {
+      const data = { username: undefined };
+      const field = 'username';
+      const message = 'Username should be a upper case string';
+      const args = [];
+      try {
+        const passes = yield Validations.present(data, field, message, args);
+        expect(passes).not.to.exist();
+      } catch (e) {
+        expect(e).to.equal(message);
+      }
+    });
+
+  });
+
 });