How to use the fxjs.group_by function in fxjs

cmap(async function(me) {
              const f_key_ids = uniq(filter((r) => !!r, pluck(me.left_key, results)));
              if (me.rel_type == '-' || !f_key_ids.length) return recur([me, cat(map(r => r._ ? r._[me.as] : null, results))]);
              return go(
                (!me.left_join_over && me.left_joins.length ?
                  left_join_query : where_in_query)(me, SQL `WHERE ${IN(me.as + '.' + me.key, f_key_ids)}`, QUERY),
                group_by((v) => v[me.key]),
                function(groups) {
                  each(function(result) {
                    result._ = result._ || {};
                    result._[me.as] = (groups[result[me.left_key]] || []);
                  }, results);
                  return recur([me, cat(map(r => r._ ? r._[me.as] : null, results))]);
                }
              );
            }),
            () => results

FROM information_schema.columns 
      WHERE
        table_name in (
          SELECT tablename 
          FROM pg_tables
          WHERE 
            tableowner=${connection_info.user || process.env.PGUSER} 
        ) ORDER BY table_name;`,
    group_by((v) => v.table_name),
    map(v => pluck('column_name', v))),
    await go(QUERY `
      SELECT * 
      FROM INFORMATION_SCHEMA.view_column_usage
      WHERE view_catalog=${connection_info.database || process.env.PGDATABASE}
      ;`,
    group_by((v) => v.view_name),
    map(v => pluck('column_name', v)))
  );

  function where_in_query(left, where_in, QUERY) {
    const colums = uniq(add_column(left).originals.concat(left.key));
    const query = left.query();
    if (query && query.text) query.text = query.text.replace(/^\s*WHERE/i, 'AND');
    return left.row_number.length == 2 ?
      QUERY `
      SELECT *
      FROM (
        SELECT
          ${COLUMN(...colums)}, 
          ROW_NUMBER() OVER (PARTITION BY ${CL(left.key)} ORDER BY ${left.row_number[1]}) as "--row_number--"
        FROM ${TB(left.table)} AS ${TB(left.as)}       
        ${where_in || tag()}