Google Apps Script to split cells

gistfile1.js

function myFunction(){
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();
//get the names from column B
  var n = sheet.getRange('B:B').getValues();
  var f = [];
  for(var i=0; i<n.length; i++){
//Reformat each name and push it in array f
    f.push(reformat(n[i][0]));
  }
//Write back the reformatted name in Column C & D
  sheet.getRange('C:D').setValues(f);
}

function reformat(e){
//regex to match '&'
  var r1 = /[&]/;
//regex to match space
  var r2 = /[\s]/;
//if cell is empty, return empty
  if (e == ''){
    return ['',''];
  }
//if the cell contains '&', return first name and last name with no & sign
  else if(r1.test(e)){
    var k = e.split(/\s(?=\S*$)/);
    return [k[0].replace(r1,''),k[1]];
  }
//If it contains space only, split it to first and last name
  else if(r2.test(e)){
    return e.split(r2);    
  }
//if only first name, return first name
  else {
    return [e,''];
  }
}