fix(validations): prevent deprecation warning in isDate (#8179)

lib/utils/validator-extras.js

@@ -93,8 +93,19 @@ validator.isNull = validator.isEmpty;
 
 // isDate removed in 7.0.0
 // https://github.com/chriso/validator.js/commit/095509fc707a4dc0e99f85131df1176ad6389fc9
-validator.isDate = function (dateString) {
-  return moment(dateString).isValid();
+validator.isDate = function(dateString) {
+  // avoid http://momentjs.com/guides/#/warnings/js-date/
+  // by doing a preliminary check on `dateString`
+  const parsed = Date.parse(dateString);
+  if (isNaN(parsed)) {
+    // fail if we can't parse it
+    return false;
+  } else {
+    // otherwise convert to ISO 8601 as moment prefers
+    // http://momentjs.com/docs/#/parsing/string/
+    const date = new Date(parsed);
+    return moment(date.toISOString()).isValid();
+  }
 };
 
 exports.validator = validator;