GMail Cleanup (Google Apps Script)

gmail-cleanup.js

/**
 * Delete e-mails older than N days based on their label(s).
 * Starred/flagged e-mails are never deleted.
 *
 * Set this up as a project at https://script.google.com/
 * And create a trigger that runs `cleanUpMailers` every hour.
 */
 
var DAY = 24 * 60 * 60 * 1000;

// Maps a label to how many to expire its messages after.
const expirationDays = {
  "_expire/ultrafast": 1,
  "_expire/fast": 7,
  "_expire/med": 14,
  "_expire/slow": 31,
  "np-activism": 7,
  "_newsdaily": 5,
};

function cleanUpTest () {
  cleanUpMailers({dryRun: true});
}

function cleanUpMailers ({ dryRun = false } = {}) {
  const now = new Date();
  for (const [labelName, days] of Object.entries(expirationDays)) {
    const maxTime = new Date(now - days * DAY)
    const label = GmailApp.getUserLabelByName(labelName);
    if (!label) {
      console.warn(`No label named "${labelName}"`);
      continue;
    }

    for (const thread of label.getThreads()) {
      const threadTime = thread.getLastMessageDate();
      if (threadTime < maxTime && !thread.hasStarredMessages()) {
        console.log(`Dropping thread "${thread.getFirstMessageSubject()}" (Updated: ${threadTime})`);
        if (!dryRun) {
          thread.moveToTrash();
        }
      }
    }
  }
}