Open photos with same filename as layers

I made a quick edit to a script that I had previously hacked together. A single source folder is selected and the script will then process pairs of files, stacking one over the other at 50% opacity, then save out a JPEG into a newly named folder within the source folder. 

It is assumed that all file pairs have correct alphabetical pair names for sorting and that the total count of all files is divisible by 2.

#target photoshop

var restoreDialogMode = app.displayDialogs;
app.displayDialogs = DialogModes.NO;

main();

function main() {
    inputFolder = Folder.selectDialog("Please select the folder with Files to process");
    if (inputFolder === null) return;
    var newPath = Folder(decodeURI(inputFolder + "/Combined")); // Create sub-dir 
    if (!newPath.exists) newPath.create();
    var fileList = inputFolder.getFiles(/\.(jpg|jpeg|tif|tiff|png|psd)$/i); // Limit file format input
    fileList.sort(); // Force alpha-numeric list sort
    while (fileList.length) {
        for (var a = 0; a < 2; a++) { // Digit 2 for two files
            try {
                app.open(fileList.pop());
            } catch (e) { }
        }
        processFiles();
    }

    alert("Done!");

    function processFiles() {
        try {
            var Name = app.documents[0].name.replace(/\.[^\.]+$/, ''); // Remove file extension

            app.activeDocument = documents[1];
            app.activeDocument.activeLayer.duplicate(documents[0]);
            app.activeDocument = documents[0];

            var doc = app.activeDocument;
            doc.activeLayer.opacity = 50.0; // Layer opacity
            doc.activeLayer.blendMode = BlendMode.NORMAL; // Blend mode

            app.displayDialogs = restoreDialogMode;

        } catch (e) { }
        var saveFile = File(newPath + "/" + Name + "_Combined" + ".tif");
        saveTIFF(saveFile);
        while (app.documents.length) {
            app.activeDocument.close(SaveOptions.DONOTSAVECHANGES);
        }
    }
}

function saveTIFF(saveFile) {
    tiffSaveOptions = new TiffSaveOptions();
    tiffSaveOptions.embedColorProfile = true;
    tiffSaveOptions.byteOrder = ByteOrder.IBM;
    tiffSaveOptions.transparency = true;
    tiffSaveOptions.layers = true;
    tiffSaveOptions.layerCompression = LayerCompression.ZIP;
    tiffSaveOptions.interleaveChannels = true;
    tiffSaveOptions.alphaChannels = true;
    tiffSaveOptions.annotations = true;
    tiffSaveOptions.spotColors = true;
    tiffSaveOptions.saveImagePyramid = false;
    // NONE | JPEG | TIFFLZW | TIFFZIP
    tiffSaveOptions.imageCompression = TIFFEncoding.TIFFLZW;
    app.activeDocument.saveAs(saveFile, tiffSaveOptions, true, Extension.LOWERCASE);
}

The script can be modified to save out a TIFF if it otherwise performs as required... What TIFF save options are needed?

EDIT: I have updated the code with TIFF save options rather than JPEG.

https://prepression.blogspot.com/2017/11/downloading-and-installing-adobe-scripts.html