JSFiddle - React, Tailwind, and code Playground

JavaScript

var a = 'MAIN_DOMAINNAME';

if ( /^(MAIN_DOMAINNAME|DOMAIN_SERIAL|DOMAIN_REFRESH|DOMAIN_RETRY|DOMAIN_EXPIRE|DOMAIN_NEGTTL|MAIN_NS)$/.test(a) ) {
    console.log('ok')
}