Subtract 30 minutes from time value - 2021-05-12T19:30:00

[admin]

Code:

str = '2021-06-01T00:00:00'

date = {}

-- assign table keys for further conversion
date.year, date.month, date.day, date.hour, date.min, date.sec =
  str:match('(%d+)-(%d+)-(%d+)T(%d+):(%d+):(%d+)')

-- convert to unix timestamp and subtract 30 minutes in seconds
timestamp = os.time(date) - 30 * 60

-- convert timestamp to string
result = os.date('%Y-%m-%dT%H:%M:%S', timestamp)
log(result)