fix(date-picker): ignore timezone in date-picker

src/forms/form-fields/date-select.js

@@ -1,6 +1,7 @@
 import React from 'react';
 import DatePicker from 'material-ui/DatePicker/DatePicker';
 import IconButton from 'material-ui/IconButton/IconButton';
+import { getISOFormatLocalTimestamp } from '../../utils/date';
 
 export default React.createClass({
     propTypes: {
@@ -27,6 +28,7 @@ export default React.createClass({
             ...other
         } = this.props;
 
+
         return (
             <div style={{ ...this.props.style }}>
                 <DatePicker
@@ -74,9 +76,11 @@ export default React.createClass({
     },
 
     _onDateSelect(event, date) {
+        // selector gives date in local time, but we want to remove "timezone"-info
+        const correctedLocalDate = getISOFormatLocalTimestamp(date);
         this.props.onChange({
             target: {
-                value: date,
+                value: correctedLocalDate
             },
         });
     },

src/utils/date.js

@@ -0,0 +1,11 @@
+/**
+ * Formats the date to an ISO string where the timezone of date is ignored before conversion to UTC.
+ * 
+ * This is useful for date-selectors where we get information with timezone information,
+ * but we are just interested in the date itself, and don't want the time to be adjusted when converting to UTC.
+ * @param {Date} date - the date to convert to an UTC ISO string
+ * @returns date formatted as ISO string without timezone information
+ */ 
+export const getISOFormatLocalTimestamp = date =>
+    new Date(date.getTime() - date.getTimezoneOffset() * 60000)
+        .toISOString()