Return from a specific date

The following code will work when assign as a custom chart study or as a custom watchlist column. Note than when applied to a custom watchlist column it will not sort correctly because the value is displayed as text. The very first line contains the user input for the date. The date you enter must be a day the markets were open for regular trade or else the code will fail.

input targetDate = 20210104;
rec targetPrice = if DaysFromDate(targetDate) == 0 then close else targetPrice[1];
def percentChange = Round(100 * (close / targetPrice - 1), 2);
AddLabel(yes, Concat("Percent Change: ", percentChange), if percentChange > 0 then Color.GREEN else Color.RED);