Lists Gmail Labels in Apps Script

listGmailLabels.js

function myFunction() {
  var labels = GmailApp.getUserLabels();
  labels[0].getName()
  var sortedLabels = labels.sort(function (label1, label2) {
    var a = label1.getName().toLowerCase();
    var b = label2.getName().toLowerCase();
    if(a < b) { return -1; }
    if(a > b) { return 1; }
    return 0;
  })
  
  for (var i = 0; i < sortedLabels.length; ++i) {
    var label = sortedLabels[i];
    Logger.log(label.getName());
  }
}

/**
[18-10-29 18:05:00:660 PDT] Boomerang
[18-10-29 18:05:00:660 PDT] Boomerang-Outbox
[18-10-29 18:05:00:661 PDT] Boomerang-Outbox/Cancelled
[18-10-29 18:05:00:662 PDT] Boomerang-Returned
[18-10-29 18:05:00:662 PDT] DubHacks
[18-10-29 18:05:00:663 PDT] NEED TO REPLY
[18-10-29 18:05:00:664 PDT] Notes
[18-10-29 18:05:00:664 PDT] Personal
[18-10-29 18:05:00:665 PDT] Receipts
[18-10-29 18:05:00:666 PDT] Sent Messages
[18-10-29 18:05:00:666 PDT] sponsor@dubhacks.co
[18-10-29 18:05:00:667 PDT] Travel
[18-10-29 18:05:00:668 PDT] Work
**/