Regular expression to validate domains ending in .mygoogle.com and .google.com:

`function isValidDomain(domain) {
const validDomainsRegex = /^(?:\w+.)?(mygoogle.com|google.com)$/;
return validDomainsRegex.test(domain);
}

// Test the function
const domain1 = 'https://www.mygoogle.com';
const domain2 = 'https://www.google.com';
const domain3 = 'https://www.twitter.com';

console.log(isValidDomain(domain1)); // true
console.log(isValidDomain(domain2)); // true
console.log(isValidDomain(domain3)); // false`