department-of-veterans-affairs/vets-website

/**
 * @typedef {Object} ParsedPhoneNumber
 * @property {string} contact - the "raw" phone number, used to populate the tel: link
 * @property {string} extension - the extension, can be any number of digits
 */

/**
 * Parses a phone number string for use with the Telephone component.
 * @param phone {String} "raw" phone number. The first 10 digits are treated as the "main" number.
 * Any remaining digits are treated as the extension.
 * Non-digits preceding the extension are ignored.
 * @returns {ParsedPhoneNumber}
 */

export const parsePhoneNumber = phone => {
  if (!phone) {
    return { contact: null, extension: null };
  }
  let sanitizedNumber = phone
    .replace(/[()\s]/g, '') // remove parentheses
    .replace(/(?<=.)([+.*])/g, '-'); // replace .*+ symbols being used as dashes

  // return null for non-US country codes
  if (sanitizedNumber.match(/\+(\d+)[^\d1]/g)) {
    return { contact: null, extension: null };
  }

  // remove US country codes +1 or 1
  sanitizedNumber = sanitizedNumber.replace(/^(\+1|1)\s*/, '');

  // capture first 10 digits + ext if applicable
  const parserRegex = /^(\d{10})(\D*?(\d+))?/;
  const contact = sanitizedNumber.replace(/-/g, '').replace(parserRegex, '$1');
  const extension =
    sanitizedNumber
      .replace(/-/g, '')
      .replace(parserRegex, '$3')
      .replace(/\D/g, '') || null;

  const isValidContactNumberRegex = /^(?:[2-9]\d{2})[2-9]\d{2}\d{4}$/;

  if (isValidContactNumberRegex.test(contact)) {
    return { contact, extension };
  }
  return { contact: null, extension: null };
};