code: async function convert(filename, options) {
      let file;
      if (filename) {
          file = fs.readFileSync(filename).toString();
      } else {
          file = await read_stdin();
      }
      try {
          file = JSON.parse(file);
      } catch {}
      let tbl = table(file);
      let view = tbl.view();
      let out;
      options.format = options.format || "arrow";
      if (options.format === "csv") {
          out = await view.to_csv();
      } else if (options.format === "columns") {
          out = JSON.stringify(await view.to_columns());
      } else if (options.format === "json") {
          out = JSON.stringify(await view.to_json());
      } else {
          out = await view.to_arrow();
      }
      if (options.format === "arrow") {
          if (options.output) {
              fs.writeFileSync(options.output, new Buffer(out), "binary");
          } else {
              console.log(new Buffer(out).toString());
          }
      } else {
          if (options.output) {
              fs.writeFileSync(options.output, out);
          } else {
              console.log(out);
          }
      }
      view.delete();
      tbl.delete();
  }
docs: Convert data from one format to another.
  
  @param {*} filename
  @param {*} options