nameInverter.js

const nameInverter = function(name) {
  const honorifics = ['MR.', 'MRS.', 'MS.', 'DR.'];
  switch (name) {
    case '':
      return '';
    case undefined:
      throw new Error('Name is undefined');
  }
  let newName = name.trim();

  // i know this is lame, but it's fast
  if (newName.toUpperCase() === 'MR.' || newName.toUpperCase() === 'MRS.' || newName.toUpperCase() === 'DR.' || newName.toUpperCase() === 'MS.') return '';

  const nameArray = newName.split(' ');

  if (nameArray.length === 2) {
    if (nameArray.some(item => honorifics.includes(item.toUpperCase()))) {
      return newName;
    } else {
      return nameArray[1] + ', ' + nameArray[0];
    }
  }

  if (nameArray.length === 3) return nameArray[0] + ' ' + nameArray[2] + ', ' + nameArray[1];

  return newName;
};

module.exports = nameInverter;