Convert between ISO8601 and FileMaker Time formats

FMCF ISO8601_time_functions.md

ISO8601GetTime(isoDate)

Let ( 
  [
	_input_date = Filter( GetValue( Split( isoDate; "T" ); 1 ); "0123456789");
	_input_time = Filter( GetValue ( Split ( GetValue( Split( GetValue( Split( isoDate; "T" ); 2 ) ; "+" ); 1) ; "-" ) ; 1 ); "0123456789.");
	_hour = Left(_input_time;2);
	_minute = Middle ( _input_time ; 3 ; 2 );
	_seccond = Middle ( _input_time ; 5 ; 99 )
  ] ;
  Time ( _hour; _minute; _seccond )
)

ISO8601FormatTime(fmTimestamp)

Case ( 
  not IsEmpty ( fmTime ) ; 
  Right ( "0" & Hour( fmTime ) ; 2 ) & ":" & Right ( "0" & Minute ( fmTime ) ; 2 ) & ":" & Right ( "0" & Seconds ( fmTime ) ; 2 ) 
)

ISO8601FormatTimestamp()

Case ( 
  not IsEmpty ( fmTimestamp ) ; 
  ISO8601FormatDate( fmTimestamp )  & "T" & ISO8601FormatTime ( fmTimestamp ) 
)

ISO8601ParseTime(isoDate)

Let ( 
  [
	_input_date = Filter( GetValue( Split( isoDate; "T" ); 1 ); "0123456789");
	_input_time = Filter( GetValue ( Split ( GetValue( Split( GetValue( Split( isoDate; "T" ); 2 ) ; "+" ); 1) ; "-" ) ; 1 ); "0123456789.");
	_hour = Left(_input_time;2);
	_minute = Middle ( _input_time ; 3 ; 2 );
	_seccond = Middle ( _input_time ; 5 ; 99 )
  ] ;
  Time ( _hour; _minute; _seccond )
)