facebookDeleteAllMessages.js

/**
 * Originally created by: https://github.com/mdunham/delete-fb-messages
 * Edited for the latest UI changes by Ozan Akman
 */

(function($){
  var 
      stepOne = function(){
          if (null !== $('div[aria-label="Conversation actions"]')) {
              $('div[aria-label="Conversation actions"]').click();
              setTimeout(stepTwo, 200);
          } else {
              console.log('There are no messages to delete');
          }
      },
      stepTwo = function(){
          var elements = document.evaluate('//span[text()="Delete"]', document, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);
          for (var i = 0; i < elements.snapshotLength; i++) {
              elements.snapshotItem(i).click();
          }
          setTimeout(stepThree, 200);
      },
      stepThree = function(){
        var elements = document.evaluate('//button[text()="Delete"]', document, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);
        for (var i = 0; i < elements.snapshotLength; i++) {
            elements.snapshotItem(i).click();
        }
          if (null !== $('div[aria-label="Conversation actions"]')) {
              setTimeout(stepOne, 600);
          } else {
              console.log('No more messages to delete');
          }
      };
  
  stepOne();
})(function(sel){ return document.querySelector(sel); });