Layers

This script takes a peek into the layers.
It makes use of the printable option to make the layer invisible. It is NOT the visible option (the tiny eye on the layer panel). have a deeper look into layers and their props here:
http://jongware.mit.edu/idcs6js/pc_Layer.html

/*
     This script takes a peek into the layers
     It makes use of the printable option to make the layer invisible
     it is NOT the visible option (the tiny eye on the layer panel)
     have a deeper look into layers and their props here:
     http://jongware.mit.edu/idcs6js/pc_Layer.html
    */
main();
function main() {
	var redrawState = app.scriptPreferences.enableRedraw; // save the initial state
	app.scriptPreferences.enableRedraw = true; // enable redraw // seems not to work well
	/*
        Lets create a nice document with lots of presets.
        To do that we define some variables for better handling
        */
	var pw = 200; // the PageHeight
	var ph = 200; // the PageWidth
	var gutter = 23; // the Gutter from the Margins to the page border
	var columns_num = 3; // the columns in the layout
	var columns_gutter = 5;
	/* Create a doc with some properties */
	var doc = app.documents.add({
		documentPreferences: {
			facingPages: false,
			pageWidth: pw,
			pageHeight: ph,
		},
		viewPreferences: {
			horizontalMeasurementUnits: MeasurementUnits.MILLIMETERS,
			verticalMeasurementUnits: MeasurementUnits.MILLIMETERS,
		},
	});
	/* set some properties on the pages */
	var page = doc.pages[0];
	page.properties = {
		marginPreferences: {
			top: gutter,
			left: gutter,
			right: gutter,
			bottom: gutter,
			columnGutter: columns_gutter,
			columnCount: columns_num,
		},
	};
	var first_layer = doc.layers.item(0); // get the first layer
	first_layer.name = "Printable Layer"; // rename it
	/*
    Add a text frame wit home properties
    The text frame will be on the first layer.
    Whenever you multiple layers the text frame will be created on the last used / active Layer
    Set or get the active Layer via:
    app.documents.item(0).activeLayer = app.documents.item(0).layers.item(X);
    */
	var first_textframe = page.textFrames.add({
		geometricBounds: [gutter, gutter, ph - gutter, pw - gutter],
		contents: "Now You see me!",
		textFramePreferences: {
			verticalJustification: VerticalJustification.CENTER_ALIGN,
		},
	});
	var firstPar = first_textframe.paragraphs[0]; // get the first paragraph
	// set some properties
	firstPar.properties = {
		pointSize: 23,
		justification: Justification.CENTER_ALIGN,
		hyphenation: false,
	};
	/*
    Lets get to the gist.
    you can duplicate layers like everything else.
    When you do that all the objects from the duplicated layer are also duplicated
    */
	var second_layer = first_layer.duplicate(false); // make a copy of the first layer
	second_layer.name = "Non Printable Layer"; // give it a name
	second_layer.printable = false; // now this layer wont show in the preview
	second_layer.textFrames.item(0).remove(); // a layer has also a collection of textFrames lets remove the duplicated tf
	alert("I will move the text frame to the non printable layer in 2 seconds"); // Talk a bit
	// set to preview  mode
	// all content of the non printable layer wont show
	app.activeWindow.screenMode = ScreenModeOptions.PREVIEW_TO_PAGE;
	/*
    all the following actions cant be seen by the user because they happen on a
    non displayed layer via the printable option NOT the visible option
    */
	first_textframe.itemLayer = second_layer; // move the text frame
	first_textframe.contents = "Now You don't"; // add some text just for fun
	first_textframe.itemLayer = first_layer; // now move the tf back to the printable layer
	first_textframe.contents = "Now You see me!"; // change the content
	app.scriptPreferences.enableRedraw = redrawState; // !Achtung! reset this to the initial state!
}

This solves the problem: "Export a single layer as a new document in InDesign"

Written for this graphicdesign.stackexchange.com question.

        // this script saves the current doc as a new one (with prompt)
        // and removes all layers except for the one
        // the user chooses in a drop down
        // main function
        var main = function() {
          // if there is no doc
          // abort
          if (app.documents.length === 0) {
            return;
          }

          var doc = app.activeDocument; // get the current active doc
          var path = doc.filePath; // get the path

          var name = prompt("Enter a name"); // get a name
          if (name.length === 0) {
            // if the user is to lazy add the date
            name = (new Date()).toString();
          }

          var layernames = [];// to store the layer names
          // loop the layer array
          for (var i = 0; i < doc.layers.length; i++) {
            layernames.push(doc.layers[i].name);// get the name
          }
          // save the doc as a new one
          // under the new name
          doc.save(new File(path + "/" + name + ".indd"));
          // add a small dialog to select the layers
          var diag = app.dialogs.add({
            name: "Layers",
            canCancel: true
          });
          // needs a column for the dropdown
          var column = diag.dialogColumns.add();
          // add the dropdown
          var layerdd = column.dropdowns.add({
            stringList: layernames,
            selectedIndex: 0,
            minWidth: 75
          });
          // show the dialog
          if (diag.show() === true) {
            var ndx = layerdd.selectedIndex;// get the index
            diag.destroy(); // remove dialog
            // move the layer to top
            doc.layers[ndx].move(LocationOptions.AT_BEGINNING);
            // remove all other layers
            for (var j = doc.layers.length - 1; j >= 1; j--) {
              doc.layers[j].remove();
            }
          }
          // THE END
        };
        main(); // run that thing
    ```