MongoClient client = new MongoClient(GetMongoSettings());
IMongoDatabase db = client.GetDatabase("test");
IMongoCollection<BsonDocument> collection = db.GetCollection<BsonDocument>("collection");
BsonJavaScript map = new BsonJavaScript(MapJs);
BsonJavaScript reduce = new BsonJavaScript(ReduceJS);
FilterDefinitionBuilder<BsonDocument> filterBuilder = new FilterDefinitionBuilder<BsonDocument>();
FilterDefinition<BsonDocument> filter = filterBuilder.Empty;
MapReduceOptions<BsonDocument, BsonDocument> options = new MapReduceOptions<BsonDocument, BsonDocument>
{
     Filter = filter,
     MaxTime = TimeSpan.FromMinutes(1),
     OutputOptions = MapReduceOutputOptions.Reduce("Result", nonAtomic: true),
     Verbose = true
};
try
{
     var mapredResult = collection.MapReduce(map, reduce, options).ToList();
}
catch (Exception ex)
{
     Console.WriteLine($"Exception occurred {ex.Message}");
}

var mapper = new BsonJavaScript(@"function()
{
 for (var columns in this)
 {
 if (!this[columns] || Object.prototype.toString.call(this[columns]) == '[object BSON]')
 getNestedColumns(columns, this[columns]);
 else
 emit(columns, this[columns]);
 }
function getNestedColumns(rootColumn, embeddedDocument)
 {
 try
 {
 for (var nestedColumn in embeddedDocument)
 {
 var columnName = rootColumn + '__' + nestedColumn;
 if (!embeddedDocument[nestedColumn] && [typeof embeddedDocument[nestedColumn]].toString() == 'object' && embeddedDocument[nestedColumn] != '[object BSON]')
 {
 emit(columnName, embeddedDocument[nestedColumn]);
 }
 else if (!embeddedDocument[nestedColumn] && isObject(embeddedDocument[nestedColumn]))
 {
 getNestedColumns(columnName, embeddedDocument[nestedColumn]);
 }
 else
 {
 emit(columnName, embeddedDocument[nestedColumn]);
 }
 }
 }
 catch (error)
 {}
 }
}");

var reducer = new BsonJavaScript(@"function(key, value)
{
    if (value[0] != null)
    {
        var integerValue = TryParseInt(value[0].toString(), null);
        if (integerValue !== null)
            return integerValue;
        var floatValue = TryParseFloat(value[0].toString(), null);
        if (floatValue !== null)
            return floatValue;
        var dateTimeValue = TryParseDateTime(value[0].toString(), null);
        if (dateTimeValue !== null)
            return dateTimeValue;
        var booleanValue = TryParseBoolean(value[0].toString(), null);
        if (booleanValue !== null)
            return booleanValue;
        return value[0].toString();
    }
    else
        return '';
}function TryParseInt(str, defaultValue)
{
    var retValue = defaultValue;
    if (str !== null)
    {
        if (str.length > 0)
        {
            if (!isNaN(str))
            {
                retValue = parseInt(str);
            }
        }
    }
    return retValue;
}function TryParseFloat(str, defaultValue)
{
    var retValue = defaultValue;
    if (str !== null)
    {
        if (str.length > 0)
        {
            if (!isNaN(str))
            {
                retValue = parseFloat(str);
            }
        }
    }
    return retValue;
}function TryParseDateTime(str, defaultValue)
{
    var retValue = defaultValue;
    if (str !== null)
    {
        if (str.length > 0)
        {
            var d = new Date(str);
            if (d != 'Invalid Date')
                return d;
            else
                return null;
        }
    }
    return retValue;
}function TryParseBoolean(str, defaultValue)
{
    var retValue = defaultValue;
    if (str !== null)
    {
        if (str.length > 0)
        {
            switch (str)
            {
                case true:
                case 'true':
                    return true;
                case 'false':
                case false:
                    return false;
                default:
                    return null;
            }
        }
    }
    return retValue;
}");