JSON object parser. Each leaf node of the object will be keyed by a concatenated key made up of all parent keys

metric_logster.js

/**
    Parses a Json Object.

    The object will be traversed, and each leaf node of the object will
    be keyed by a concatenated key made up of all parent keys.
**/
function MetricLogster(reporter) {

}

function isArray(obj) {
    return obj.constructor === Object;
}


function isObject(obj) {
    return obj.constructor === Array;
}

// we assume that if it is not another object or array
// it is a primitive type
// obviously not true in javascript but true for this module usage
function isPrimitive(item) {
    return !isObject(item) && !isArray(item);
}


/**
 * Recurses through objectsand flattens them
 * into a single level dict of key: value pairs.  Each
 * key consists of all of the recursed keys joined by
 * separator that is hardcoded to be a dot.
 **/
MetricLogster.prototype.flatten = function (obj) {
    // assert what we got was actually an object
    console.assert(isObject(obj) || isArray(obj));

    var dict = {};
    var dot = '.';

    /**
     **/
    function _flatten(obj, dict, keyPrefix) {

        if (obj === null) {
            return dict;
        }

        // object has -ad minimum - a key, value pair
        // {'some-key': 'some-value-maybe-another-object'}
        // decide if object or array

        for (var name in obj) {

            if (obj.hasOwnProperty(name)) {

                var keyName;
                if (keyPrefix) {
                    keyName = keyPrefix + dot + name;
                } else {
                    keyName = name;
                }

                if (isPrimitive(obj[name])) {
                    dict[keyName] = obj[name];
                } else {
                    // continue recursing
                    // TODO assumes objects, need to deal with arrays too
                    _flatten(obj[name], dict, keyName);

                }

            }

        }

        return dict;

    }

    return _flatten(obj, dict, null);
};


/************** Mopdule exports ***********************/

var logster = new MetricLogster();

module.exports = function (reporter) {
    // Return an application singletion
    logster.setReporter(reporter);
    return logster;
};