Google script to mine a unique list of email addresses from gmail

unique_email_addresses.gs

function getEmails() {
  // get all messages
  var allAddresses = [];
  var start = 0;
  var emailCount = 500;
  var doIt = true;
  while (doIt) {
    var emails = GmailApp.getMessagesForThreads(GmailApp.search('after:2012/9/1', start, emailCount))
    start += emails.length;
    doIt = emailCount == emails.length;
    
    var addresses = emails.reduce(function(a, b) {
        //flatten out array of array of messages
        return a.concat(b);
      })
      .map(function(eMails) {
        // pull all email addresses from email into array
        var adds = [eMails.getFrom().toLowerCase()];
        adds = adds.concat(eMails.getTo().toLowerCase().split(", "));
        adds = adds.concat(eMails.getCc().toLowerCase().split(", "));
        adds = adds.concat(eMails.getBcc().toLowerCase().split(", "));
        return adds;
      })
      .reduce(function(a, b) {
        // concat all addresses from all emails into one array
        return a.concat(b);
      }, [])
      .filter(function(a) {
        //filter out empty elements, or elements without an @ sign
        return a.trim().length > 0 && a.search("@") >= 0;
      })
      .map(function(email) {
        // pull out just the email address from each item
        var start = email.indexOf("<");
        var end = email.indexOf(">");
        if (start >= 0) {
          return email.substring(start+1, end);
        }
        return email;
      })
      .sort()
      .filter(function(el,i,a){
        //filter for unique entries
        if(i==a.indexOf(el))return 1;return 0
      });

    allAddresses = allAddresses.concat(addresses)
  }
  
  // sort and filter for unique entries...one more time!
  allAddresses = allAddresses.sort()
  .filter(function(el,i,a){
    if(i==a.indexOf(el))return 1;return 0
  })
  .sort(function(a, b) {
    // sort emails by domain
    return a.substring(a.indexOf("@")+1).localeCompare(b.substring(b.indexOf("@")+1));
  });
  
  // create 2D-array
  var aUnique = new Array();  
  for(var k in allAddresses) {
    aUnique.push([allAddresses[k]]);
  }

  // add data to sheet
  SpreadsheetApp.getActiveSheet().getRange(1, 1, aUnique.length, 1).setValues(aUnique);
} 

Failing test case:

To: "Jim, Savers" <[email protected]>

it will tokenize on the , inside the email