HOSTNAME
A host name as DNS has them: labels of letters, digits and hyphens, at least two, the last not all digits.
export const HOSTNAME = /^(?=.{1,253}$)(?:[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?\.)+[a-z][a-z0-9-]{0,61}[a-z0-9]$/i
A host name as DNS has them: labels of letters, digits and hyphens, at least two, the last not all digits.
export const HOSTNAME = /^(?=.{1,253}$)(?:[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?\.)+[a-z][a-z0-9-]{0,61}[a-z0-9]$/i