Angular email REGEX is :
/^[a-z0-9!#$%&'+/=?^_`{|}~.-]+@a-z0-9?(.a-z0-9?)$/i
I understand everything but I'm not sure what does the i at the end mean.
It is the only REGEX having it:
var ISO_DATE_REGEXP = /\d{4}-[01]\d-[0-3]\dT[0-2]\d:[0-5]\d:[0-5]\d\.\d+([+-][0-2]\d:[0-5]\d|Z)/; var URL_REGEXP = /^(ftp|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?$/; var EMAIL_REGEXP = /^[a-z0-9!#$%&'*+\/=?^_`{|}~.-]+@[a-z0-9]([a-z0-9-]*[a-z0-9])?(\.[a-z0-9]([a-z0-9-]*[a-z0-9])?)*$/i; var NUMBER_REGEXP = /^\s*(\-|\+)?(\d+|(\d*(\.\d*)))([eE][+-]?\d+)?\s*$/; var DATE_REGEXP = /^(\d{4})-(\d{2})-(\d{2})$/; var DATETIMELOCAL_REGEXP = /^(\d{4})-(\d\d)-(\d\d)T(\d\d):(\d\d)(?::(\d\d)(\.\d{1,3})?)?$/; var WEEK_REGEXP = /^(\d{4})-W(\d\d)$/; var MONTH_REGEXP = /^(\d{4})-(\d\d)$/; var TIME_REGEXP = /^(\d\d):(\d\d)(?::(\d\d)(\.\d{1,3})?)?$/; 
/iis a flag, it means case insensitive.