feat: Capture epoch time in DateInput

editor.planx.uk/src/@planx/components/DateInput/Public.test.tsx

@@ -87,6 +87,7 @@ test("recovers previously submitted date when clicking the back button even if a
   expect(handleSubmit).toHaveBeenCalledWith({
     data: {
       [dataField]: "2010-05-22",
+      [dataField + ".epoch"]: 1274486400,
     },
   });
 });

editor.planx.uk/src/@planx/components/DateInput/Public.tsx

@@ -12,7 +12,7 @@ import InputRow from "ui/shared/InputRow";
 import { object } from "yup";
 
 import { DESCRIPTION_TEXT, ERROR_MESSAGE } from "../shared/constants";
-import { getPreviouslySubmittedData, makeData } from "../shared/utils";
+import { getPreviouslySubmittedData } from "../shared/utils";
 
 export type Props = PublicProps<DateInput>;
 
@@ -22,7 +22,16 @@ const DateInputPublic: React.FC<Props> = (props) => {
       date: getPreviouslySubmittedData(props) ?? "",
     },
     onSubmit: (values) => {
-      props.handleSubmit?.(makeData(props, values.date));
+      props.handleSubmit?.({
+        data: props.fn
+          ? {
+            // Capture user data as ISO 8601
+            [props.fn]: values.date,
+            // Capture user data as epoch time (for use in calculate component)
+            [props.fn + ".epoch"]: new Date(values.date).valueOf() / 1000,
+          }
+          : undefined
+      });
     },
     validateOnBlur: false,
     validateOnChange: false,