pattern constant
String
const pattern
Implementation
static const String pattern =
r"^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]"
r"{0,253}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]"
r"{0,253}[a-zA-Z0-9])?)*$";