JXA：删除文件夹，创建新文件夹，将匹配的文件移到新文件夹

Question

我是JXA的新手，所以我确定还有很多我不知道的地方。我是一名Javascript开发人员，但只研究了一天。这是我想要做的：

我的MacBookPro上有很多文件夹，其中装有mp4格式的视频课程。为了使Plex可以将它们作为电视节目观看（这似乎是浏览这些节目的最佳方法），需要将它们重命名并移到“第1季”文件夹中。我尝试了几个脚本示例来完成此操作，但是我仍然遇到我无法理解的错误。这是我脚本的最新版本（根本不解决重命名文件的问题）：

var currentApp = Application.currentApplication();
currentApp.includeStandardAdditions = true;
var finder = Application("Finder");
var systemEvents = Application("System Events");
var folderName = "Season 1";
var extensionsToProcess = ["mp4","mkv","mpg","mov"] // For example: {"jpg", "jpeg"}, NOT: {".jpg", ".jpeg"}

// Ask a folder to process
var sourcePath = currentApp.chooseFolder ({
    withPrompt: "Choose the source folder"
}).toString();
var sourceFolder = systemEvents.aliases.byName(sourcePath);

// Create the destination folder
var container = sourceFolder.container();
var containerPath = container.path();
var destinationFolder = finder.make({
  new: "folder", at: containerPath,
  withProperties: { name: folderName }
});

// Create an array of items to be processed
var items = systemEvents.aliases.byName(sourcePath).diskItems;
var selectedItems = [];

for (var i = 0; i < items.length; i++) {
  var item = items[i];
  if (item.class() != "folder" && item.visible()) {
    selectedItems.push(item.name());
  }
}

// Process every item
var createdFolders = [];
selectedItems.forEach(function(itemName) {
  var item = systemEvents.aliases.byName(sourcePath + "/" + itemName);
  var extension = item.nameExtension();
  var name = item.name().match(/(.*) - (.*)/);

  if (extensionsToProcess.includes(extension)) {
    try {
      var folderName = sourceFolder;
      if (!createdFolders.includes(folderName)) {
        var newFolder = finder.make({
          new: "folder", at: destinationFolder, withProperties: { name: folderName }
        });
        createdFolders.push(folderName);
      }
      item = finder.move(item.path(), { to: destinationFolder.folders[folderName] });
      item.name = name[2];
    } catch (error) {
      console.log("Error (item: " + item.name() + "): " + error);
    }
  }
});

我当前在尝试创建一个新文件夹（destinationFolder）的行上遇到错误，该文件夹说该文件夹已存在，但实际上不存在，因此显然我在这里有点迷失了。任何帮助将不胜感激！