/
(?x)
^(?!.*[\s]) # this excludes whitespaces
(?=.*\d) # this matches at least one digit
(?=.*[a-z]{0,}) # this matches 0 or more lowercase letters
(?=.*[A-Z]) # this matches at least one uppercase character
.{8,}$ # ensuring the minimum length is 8 symbols
# ^(?!.*[\s])(?=.*\d)(?=.*[a-z]{0,})(?=.*[A-Z]).{8,}$ the whole RegEx
/
gm