func.js

/**
 * Selman Kahya, 2013
 * See project's Github page for usage details.
 * https://github.com/Selmanh
 */

/**
 * takes nested mysql result array as a parameter,
 * converts it to a nested object
 *
 * @param {Array} rows
 * @param {Array} nestingOptions
 * @return {Object}
 */
exports.convertToNested = function (rows, nestingOptions) {

    if (rows == null || nestingOptions == null)
        return rows;

    var levels = nestingOptions;

    // put similar objects in the same bucket (by table name)
    var buckets = new Array();

    for (var i = 0; i < levels.length; i++) {
        var result = new Array();

        var level = levels[i];
        var key = level.key;
        var tableName = level.tableName;

        for (var j = 0; j < rows.length; j++) {
            var object = rows[j][tableName];

            // check if object has key property
            if (object == null){
                console.log("Error: couldn't find " + tableName + " property in mysql result set")
                continue;
            }

            // if object isn't in result array, then push it
            if(!isExist(result, key, object[key]))
                result.push(object);
        }
        buckets.push(result);
    }

    // we have similar objects in the same bucket
    // now, move lower level objects into related upper level objects
    for (var i = buckets.length-1; i >= 1; i--) {
        var relationKey = levels[i-1].key;
        var relationTable = levels[i].tableName;
        var objects = buckets[i];

        for (var j = 0; j < objects.length; j++) {

            var value, indexes = null;
            var object = objects[j];

            // if couldn't find foreign key value in upper level, look to upper levels
            var targetBucket, a = 1;
            while(indexes == null && (i-a) >= 0){
                targetBucket = buckets[i-a];

                // if lower level table doesn't have upper level table's primary column as foreign key
                // then upper table has a foreign key to lower table
                if(levels[i].hasOwnProperty('hasForeignKeyToUpperTable') && !levels[i].hasForeignKeyToUpperTable)
                    relationKey = levels[i].key;
                else
                    relationKey = levels[i-a].key;

                value = object[relationKey];
                indexes = getIndexes(targetBucket, relationKey, value);
                a++;
            }

            // relation to upper object(s) not found - ignore this object
            if(indexes == null || indexes.length == 0)
                continue;

            for(var z = 0; z < indexes.length; z++){
                if(!targetBucket[indexes[z]][relationTable])
                    targetBucket[indexes[z]][relationTable] = new Array();

                targetBucket[indexes[z]][relationTable].push(object);
            }
        }
    }

    // at the end, we have all the nested objects in the first bucket
    return buckets[0];
};


/**
 * returns indexes of the object that has given key property,
 * and the value of that property equals to given value
 *
 * @param {Array} objects
 * @param {String} key
 * @param {String} value
 * @return {Array}
 */
var getIndexes = function(objects, key, value){

    if (objects == null || key == null || value == null)
        return null;

    var result = new Array();

    for (var i = 0; i < objects.length; i++) {
        if(objects[i][key] == value){
            result.push(i);
        }
    }

    return result;
}

/**
 * checks if one of the objects in an array has the given property,
 * and the value of that property equals to given value
 *
 * @param {Array} array
 * @param {String} key
 * @param {String} value
 * @return {Array}
 */
//
var isExist = function(array, key, value){

    for (var i = 0; i < array.length; i++) {
        if(array[i][key] == value)
            return true;
    }

    return false;
}