[Fix #237] Fixed issue with incorrect date values

src/components/answer/DateTimeAnswer.jsx

@@ -1,7 +1,7 @@
 import React, { useContext } from "react";
 import DatePicker from "react-datepicker";
 import { FormGroup, Form } from "react-bootstrap";
-import PropTypes, { number } from "prop-types";
+import PropTypes from "prop-types";
 import { format } from "date-fns";
 import FormUtils from "../../util/FormUtils";
 import Constants from "../../constants/Constants";
@@ -21,9 +21,7 @@ const DateTimeAnswer = (props) => {
 
   // workaround because it is not possible to construct Date only with time
   let value;
-  if (isTime && props.value instanceof number) {
-    value = new Date(`0 ${props.value}`);
-  } else if (isDate && props.value instanceof number) {
+  if ((isTime || isDate) && props.value && props.value !== "0") {
     value = new Date(props.value);
   } else value = null;