_hstore.js

"use strict";

var pattern = '("(?:\\\\\"|[^"])*?")\\s*=>\\s*((?:"(?:\\\\\"|[^"])*?")|NULL)';
var re = new RegExp(pattern,'gi');

exports.json_to_hstore = function json_to_hstore (json) {
    if (typeof json == 'string') json = JSON.parse(json);
    var hstore = [];
    for (var key in json) {
        var value = json[key];
        value = value === null ? 'NULL' : JSON.stringify(value.toString());
        hstore.push('"' + key + '" => ' + value);
    }
    return hstore.join(', ');
}

exports.hstore_to_json = function hstore_to_json (string) {
    var key, value;

    var result = {};
    var match = null;

    while((match = re.exec(val)) != null) {
        key = JSON.parse(match[1]);
        value = match[2] == "NULL" ? null : JSON.parse(match[2]);
        result[key] = value;
    }

    return result;
}