how to check if a string is valid email javascript code example

Example 1: regex pattern to validate email

[a-zA-Z0-9._-]{3,}@[a-zA-Z0-9.-]{3,}\.[a-zA-Z]{2,4}

Example 2: code for email verification in front end using javascript

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());
}