upiId constant
Pattern
const upiId
UPI ID Regex (e.g. mobile@upi or username@bank) Accepts lowercase, digits, dot, dash, plus underscore in name; domain must be alphanumeric Examples: test.user@okaxis, 1234567890@upi
Implementation
static const Pattern upiId = r'^[a-z0-9.\-_+]{2,256}@[a-z]{2,64}$';