After Effect text number range

range.jsx

{
  app.beginUndoGroup("Script"); 
  
  compSettings                           = cs = [1280, 720, 1, 1, 24];
  currentProject                         = (app.project) ? app.project : app.newProject();
  currentComp                            = (currentProject.activeItem) ? currentProject.activeItem : currentProject.items.addComp("Timeline", cs[0], cs[1], cs[2], cs[3], cs[4]);
  currentComp.openInViewer();
  
  textLayer                              = currentComp.layers.addText("Range");
  textLayerSourceTextProperty            = textLayer.property("Source Text");
  
  startSlider                            = textLayer.Effects.addProperty("Slider Control");
  startSlider.name                       = "Start";
  startSlider.property("Slider").setValue(1);
  
  endSlider                              = textLayer.Effects.addProperty("Slider Control");
  endSlider.name                         = "End";
  endSlider.property("Slider").setValue(5);
  
  textLayerSourceTextProperty.expression = "var v = ''; \
  for(var i = effect('Start')('Slider'); i <= effect('End')('Slider'); i++) { \
    v += ' ' + i; \
  } \
  v;";
  
  app.endUndoGroup();
}