Question

I have minimal knowledge of Javascript, but would like to use this code to enhance my GMail experience. It works, but I also get errors. When I run the debugger in Google Spreadsheet, two functions appear to malfunction:

TypeError: Cannot call method "getThreads" of null. (line 59)

With the following Execution transcript

GmailApp.getUserLabelByName([FollowUp])

GmailApp.getUserLabelByName([FollowUp/1undefined])

Inserted comment: there is some information about the GMail API call getThreads (and others) here: https://developers.google.com/apps-script/class_gmaillabel#getThreads

What I don’t get is why it is calling Followup/1undefined -> why is it undefined? It should be Followup/1days

And another error with another function:

Cannot find method moveThreadsToInbox(. (line 26)

With nothing in the Execution transcript

The entire code is:

// Adapted from:
// http://gmailblog.blogspot.com/2011/07/gmail-snooze-with-apps-script.html
//
// To setup:
// - From the |Run| menu select |setup|
//   - if prompted to authorize, do so, and then repeat this step.
//
// - Verify the script is set to be triggered to run
//   - |Triggers| menu |Current script's triggers...|
//   - 3 triggers should exist to call e.g. 
//     - dailyUpdate, Time Driven, Daily

function getLabelName(i, labelSuffixString) {
  return "FollowUp/" + i + labelSuffixString;
}

function setup() {
  for (var i = 1; i <= 7; ++i) {
    GmailApp.createLabel(getLabelName(i, "days"));
    GmailApp.createLabel(getLabelName(i, "weeks"));
  }
  GmailApp.createLabel("FollowUp");
}

function moveToInbox(page) {
  GmailApp.moveThreadsToInbox(page);
  GmailApp.markThreadsImportant(page);
}

function cleanOldFollowUpLabels() {
  var searchString = "-label:inbox label:FollowUp";
  for (var i = 1; i <= 7; ++i) {
    searchString += " -label:" + getLabelName(i, "days");
    searchString += " -label:" + getLabelName(i, "weeks");
  }
  searchString = searchString.replace(RegExp("/", "g"), "-");
  Logger.log("cleanOldFollowUpLabels() Search String:");
  Logger.log(searchString);
  var followUpLabel = GmailApp.getUserLabelByName("FollowUp");  
  var page = null;
  // Get threads in "pages" of 100 at a time
  while(!page || page.length == 100) {
    page = GmailApp.search(searchString, 0, 100);
    Logger.log("found: " + page.length);
    if (page.length > 0)
      followUpLabel.removeFromThreads(page);   
  }
}

function update(labelSuffixString) {
  var oldLabel, newLabel, page;
  var followUpLabel = GmailApp.getUserLabelByName("FollowUp");
  for (var i = 1; i <= 7; ++i) {
    newLabel = oldLabel;
    oldLabel = GmailApp.getUserLabelByName(getLabelName(i, labelSuffixString));
    page = null;
    // Get threads in "pages" of 100 at a time
    while(!page || page.length == 100) {
      page = oldLabel.getThreads(0, 100);
      if (page.length > 0) {
        followUpLabel.addToThreads(page);
        if (newLabel) {
          // Move the threads into "today’s" label
          newLabel.addToThreads(page);
        } else {
          moveToInbox(page);
        }     
        // Move the threads out of "yesterday’s" label
        oldLabel.removeFromThreads(page);
      }  
    }
  }
}

function dailyUpdate() {
  update("days");
}
function weeklyUpdate() {
  update("weeks");
}

Also here: http://pastie.org/4790086.js

Answer 1

mm.. with the help of a colleague, we found the answer to my own problem. I had three triggers running: A daily trigger, a weekly trigger, and the update trigger. Now the update trigger was not necessary, because it was called upon by the daily and weekly trigger, and without any input. That caused the error. Now I have to wait and see if there are any errors and if the script works.