[Flutter] RegExp for Email.

r"(^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$)"

if (!RegExp(r'(^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$)')

.hasMatch(value)) {

return 'Email should be mail format.';

}