Example of possible usage for hstore type conversion.

test-hstore.js

var util = require('util');

var _ = require('lodash');
var pg = require('pg');

/**
 * Convert a JavaScript object to the PostgreSQL `hstore` format.
 *
 * @param object e.g. {a:1, b:2, c:3}
 * @return e.g. 'a=>1,b=>2,c=>3'
 */
function hstore(object)
{
    return _.map(object,
            function(value, key)
            {
                return util.format('"%s"=>"%s"', key, value);
            }).join(',');
} // end hstore

pg.connect({},
        function(err, client, done)
        {
            if(err)
            {
                console.error('Error connecting to PostgreSQL: %s', err.stack || err.toString());
                process.exit(1);
            } // end if

            client.query(
                    {
                        text: "SELECT keyValuePairs -> 'some' AS someValue FROM (VALUES ($1::hstore)) AS sub (keyValuePairs)",
                        values: [hstore({some: 'properties', "go here": 33})],
                    },
                    function(err, result)
                    {
                        if(err)
                        {
                            console.error('Error running query: %s', err.stack || err.toString());
                            console.log(util.inspect(err, {colors: true}));
                            process.exit(1);
                        } // end if

                        console.log(util.inspect(result.rows, {colors: true}));
                        process.exit(0);
                    });
        });