aggregate function array_agg in postgresql 8.3

CREATE AGGREGATE array_agg(anyelement) (
  SFUNC=array_append,
  STYPE=anyarray,
  INITCOND='{}'
);

function idx in postgresql 8.3

CREATE OR REPLACE FUNCTION idx(anyarray, anyelement)
  RETURNS int AS 
$$
  SELECT i FROM (
     SELECT generate_series(array_lower($1,1),array_upper($1,1))
  ) g(i)
  WHERE $1[i] = $2
  LIMIT 1;
$$ LANGUAGE sql IMMUTABLE;

node.js+postgresql

List of postgresql adapters for node.js:
https://github.com/ry/node_postgres
https://github.com/brianc/node-postgres - my select (the best)
https://github.com/creationix/postgres-js
https://github.com/aurynn/postgres-js

I execute command for use node-postgres:

npm install pg

example.js:
var pg = require('pg');
var connectionString = "pg://postgres:postgres@localhost:5432/test";
pg.connect(connectionString, function(err, client) {
    if (err) {
        console.log('fatal error');
    } else {
        client.query("select version();", function(err, result) {
            if (err) {
                console.log('error');
            } else {
                console.log(result);
            }
        });
    }
})