UXP: getItems() returns ProjectItems — how to access subfolders?

Hi @Julian5D97 ,

ProjectItems are somewhat generic objects that simply provide the starting point to accessing the specific attributes of each type of item.  For example, ClipProjectItems can do things that FolderItems can't, and vice versa.  So when you use .getItems() to get the contents of a folder, all contained items get listed as ProjectItems, and then you must inspect these items to step into further functionality for each one.  We currently use .cast() for this.

In your case, let's say you want to traverse your project folder tree.  Project.getRootItem() returns the root of the project as a FolderItem, and thus, .getItems() will work to return a list of ProjectItems found in the root.  To then determine which ProjectItems in the returned list are folders, you must try to cast each one to a FolderItem - if the cast is successful, the ProjectItem is a FolderItem; if the cast fails, the ProjectItem is not a FolderItem (note, this does not indicate what type of item the ProjectItem is, this only indicates that it is not a FolderItem!).

For the ProjectItems that have been successfully cast to FolderItems (assuming you save them to a variable), the .getItems() method will now also be available on those cast FolderItem objects for you to continue traversing the tree.

To perform the cast, use the following: 

const myFolderItem = require("premierepro").FolderItem.cast(myProjectItem);