what does regex mail code example

Example 1: regex for email

^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$
//will validate for:  [email protected] etc

Example 2: email regular expression

function validateEmail(email) {
 const re = /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
 return re.test(String(email).toLowerCase());
}