OSX JavaScript: Assign given icon to file or folder

assign_icon.jsx

#!/usr/bin/env osascript -l JavaScript

// ==========
// = Usage:
//   ./assign_icon.jsx TARGET_FILE SOURCE_IMAGE
// ==========

ObjC.import("Cocoa");

function run(input) {
  var target_path = input[0].toString();
  var source_image = $.NSImage.alloc.initWithContentsOfFile(input[1].toString());
  var result = $.NSWorkspace.sharedWorkspace.setIconForFileOptions(source_image, target_path, 0);
  return target_path;
}