Help converting Forms Date to Calendar Date-Time

Help converting Forms Date to Calendar Date-Time

I need help writing a custom Flow function to convert from the date format of a Form date field:

yyyy-mm-dd

to the date-time format of a Calendar entry:

yyyy-MM-ddTHH:mm:ssZ

The Calendar item will be an All-Day event.

It is acceptable for the Time to be hard-coded to 00:06:00

Please help with how to format the input into the Flow formatDate() function.
 
The input to Calendar is:




The error message from Calendar is:



My function is this:
  1. string formatDate(string dateStr, string fromFormat, string toFormat)
  2. {
  3. fromFormat = "yyyy-MM-dd";
  4. toFormat = " yyyy-MM-ddTHH:mm:ssZ";
  5. dateObj = dateStr.toTime(fromFormat);
  6. info dateObj;
  7. return dateObj.toString(toFormat);
  8. }