code: function checkCommonArgs(args) {
          if (args.length < 2) throw new Error("File1, File2, and callback required");
          if (typeof args.at(1) != "string") throw new Error("File2 required");
          if (typeof args.at(0) != "string") throw new Error("File1 required");
          if (!args.callbackGiven()) throw new Error("Callback required");
      }
docs: Common argument checking for crop and resize