How do I run a script on a folder which is only set to run on an individual file?

Question

I want to use the layer to file script on an entire folder of about 40 files.
I tried creating an action with "Insert menu item" but when I run the batch file it crashes illustrator.
I am thinking I should combine the savedocsasPDF example script with the layer to file script but I am having trouble. 
Would someone be able to point me in the right direction please?
Thanks!

Answer 1

I do this like so:
var inddFiles = GetFilesFromBook();
for (var i = 0; i < inddFiles.length; i++) {
    inddFile = inddFiles[i];
    app.scriptPreferences.userInteractionLevel = UserInteractionLevels.NEVER_INTERACT;
    doc = app.open(inddFile);
    app.scriptPreferences.userInteractionLevel = UserInteractionLevels.INTERACT_WITH_ALL;
    // Process document
    doc.close(SaveOptions.YES);
function GetFilesFromBook() {
    var bookContent, file,
    activeBook = app.activeBook,
    files = [];
    for (var i = 0; i < activeBook.bookContents.length; i++) {
        bookContent = activeBook.bookContents[i];
        if (bookContent.status != BookContentStatus.MISSING_DOCUMENT) {
            file = new File(bookContent.fullName);
            files.push(file);
    return files;
Here is the whole script that you can use as example.