Simplest (just connect, create, find, count) MongoDB wrapper.

mongo.ts

import {Query} from './query'
let MongoClient = require('mongodb').MongoClient;

let defaultFailure = function (err) { throw err; };

class Mongo {

    connected: boolean;
    db: any;

    constructor(public url: string) {
        this.connected = false;
    }

    connect (withDb?: Function) {
        if(! this.connected) {
            MongoClient.connect(this.url, (err, db) => {
                if(err) throw err;

                this.db = db;
                this.connected = true;
                if(withDb) withDb(this.db)
            })
        } else {
            withDb(this.db)
        }

        return this;
    }

    disconnect() {
        this.db.close();
        this.connected = false;
    }

    insert(collName: string, document: any, onSuccess: Function, onFailure?: Function) {

        let failure = onFailure || defaultFailure;

        this.connect(db => {
            db.collection(collName).insertOne(document, (err, result) => {
                // Result - http://mongodb.github.io/node-mongodb-native/2.2/api/Collection.html#~insertOneWriteOpResult
                err && failure(err) || onSuccess(result);
            })
        })
    };
    
    findAll(collName: string, query: Query, withResult: Function) {
        this.connect(db => {
            let collection = db.collection(collName);
            let condition = query.condition || {};

            let cursor = collection.find(condition);

            if(query.order) cursor.sort(query.order);
            if(query.limit) cursor.limit(query.limit);
            if(query.offset) cursor.skip(query.offset);

            cursor.toArray((err, result)  => {
                err && defaultFailure(err) || withResult(result);
            })
        })
    }

    count(collName: string, query: Query, withResult: Function) {
        this.connect(db => {
            let collection = db.collection(collName);
            let condition = query.condition || {};

            collection.count(condition).then(total => withResult(total));
        })
    }

}

module.exports = Mongo;

query.ts

export interface Query {
    condition?: Object,
    order?: Object,
    limit?: number
    offset?: number
}