Change Font.sketchplugin

// Change font (ctrl a)
var font_name = [doc askForUserInput:"Font name:" initialValue:"Arial"];

function check_layer(layer){
  log("Checking layer " + layer + " of klass: " + [layer class])
  switch ([layer class]) {
    case MSTextLayer:
      log("Found text layer!")
      layer.setFontPostscriptName(font_name);
      break;
    case MSPage:
    case MSLayerGroup:
    case MSArtboardGroup:
      var sublayers = [layer layers];
      log("This is a group/artboard/page with " + [sublayers count] + " sublayers")
      for(var i=0; i < [sublayers count]; i++) {
        var sublayer = sublayers[i];
        check_layer(sublayer);
      }
      break;
  }
}

log("################################################################")

// Use selection, if any
if(selection && [selection count]){
  for (var i = 0; i < [selection count]; i++) {
    check_layer(selection[i]);
  }
} else {
  // Otherwise, loop trough pages, artboards & layers
  var pages = [doc pages];
  for (var i = 0; i < [pages count]; i++) {
    var current_page = pages[i];
    if ([[current_page artboards] count]) {
      log("Traversing artboards")
      for (var i = 0; i < [[current_page artboards] count]; i++) {
        var artboard = [current_page artboards][i]
        check_layer(artboard)
      }
    } else {
      log("Page has no artboards")
      check_layer(current_page)
    }
  }
}