Change font family for all text layers in Sketch

Change Font.sketchplugin

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

function check_layer(layer){
  log(layer)
  var className = layer.className()
  log("Checking layer " + layer + " of klass: " + className)
  if (className == "MSTextLayer") {
    log("Found text layer!")
    layer.setFontPostscriptName(font_name);
  }
  if (className == "MSArtboardGroup" || className == "MSLayerGroup"){
    var sublayers = [layer layers];
    log("This is a group/artboard/page with " + [sublayers length] + " sublayers")
    for(var i=0; i < [sublayers length]; i++) {
      var sublayer = sublayers.objectAtIndex(i);
      check_layer(sublayer);
    }
  }
}

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

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

Getting the same error as KingWu:

ReferenceError: Can't find variable: doc

This helped me, thanks

here is my very simplified edition to replace a font with another one

function check_layer(layer) 
{

  switch ([layer class]) 
  {
    case MSTextLayer:

      var layer_font = [layer fontPostscriptName]

      if ( layer_font == ".AppleSystemUIFont" ) {

        layer.setFontPostscriptName("Play-Bold");

      }

      break;
  }
}


var doc = context.document;

// loop through layers on current page
var page = [doc currentPage]
var layers = [page children]

for (var i = 0; i < [layers count]; i++) {
  check_layer(layers[i])
}

Would be nice if later can have some sort of font mapping (i.e. change specific font A to font B & font C to font D at the same time), thanks for the work though!

This is really cool man, many thanks!

Can you provide some instruction on exactly what I need to paste into Custom Plugin please and how to change to desired font.

@Youhan Thank you buddy it helped me out and worked perfectly :)