code: async function(filename, data) {
        if (!data) {
          if (await fs.existsAsync(filename)) {
            fs.unlinkAsync(filename);
          }
        } else {
          await fs.writeFileAsync(filename, JSON.stringify(data, null, 2), "utf8");
        }
      }
docs: Saves JSON data to a file, or erases the file if data is null
  
  @param filename {String} filename to write to
  @param data {Object?} the data to write