javascript const autoHyphen = (target) => { if (target.value.indexOf('1') === 0) { // ex) 1588-**** target.value = target.value .replace(/[^0-9]/g, '') .replace(/(\d{4})(\d{4})/, '$1-$2') } else if (target.value.indexOf('02') === 0) { // ex) 02-***-**** or 02-****-**** target.value = target.value .replace(/[^0-9]/g, '') .replace(/^(\d{2})(\d{3,4})(\d{4})$/, `$1-$2-$3`); } else { // ex) 031-***-*..