Phone Mask

masks.js

const getPurePhone = (value) => {
  if (!value) {
    return '';
  }

  return value.replace(/\+7|[^\d]/g, '')
    .replace(/^8(\d{10})$/, '$1');
}

const phoneMask = (value) => {
  value = getPurePhone(value);

  const groups = value.match(/(\d{0,3})(\d{0,3})(\d{0,2})(\d{0,2})/);

  groups[1] = groups[1].padEnd(3, '_');
  groups[2] = groups[2].padEnd(3, '_');
  groups[3] = groups[3].padEnd(2, '_');
  groups[4] = groups[4].padEnd(2, '_');

  return `+7 (${groups[1]}) ${groups[2]}-${groups[3]}-${groups[4]}`;
};