How to write text to a text file by Photoshop JavaScript?

Here's what you need: It's pretty basic. It'll loop over the layers (no layersets!!) and save out the layer name and the layer bounds for each layer.

app.preferences.rulerUnits = Units.PIXELS;
var srcDoc = app.activeDocument;
var numOfLayers = srcDoc.layers.length;
var results = "";
var fileName = srcDoc.name;
var docName = fileName.substring(0,fileName.length -4)
var theFile = srcDoc.path + "/" + docName + ".txt";

for (var i = 0; i < numOfLayers  ; i++)
{
  var theLayer = srcDoc.layers[i];
  var lb = getLayerBounds(theLayer).toString();
  results += theLayer.name + ": " + lb + "\n";
}

writeTextFile(theFile, results)
alert(results);

function getLayerBounds(alayer)
{
  var x1 = parseFloat(alayer.bounds[0])
  var y1 = parseFloat(alayer.bounds[1])
  var x2 = parseFloat(alayer.bounds[2])
  var y2 = parseFloat(alayer.bounds[3])
  return [x1,y1,x2,y2]
}

function writeTextFile(afilename, output)
{
  var txtFile = new File(afilename);
  txtFile.open("w"); //
  txtFile.writeln(output);
  txtFile.close();
}

I found the docs lacking but came up with this as a method to create and write to a new file in CS6:

var s = "My string data here";
var file = new File();
var fileNew = file.saveDlg("Save new file");
fileNew.open("w");
fileNew.write(s);
fileNew.close();