The best way to store multilingual data in MongoDB

Coincidentally, I am in the process of thinking through a new application using Node and MongoDB.

I have lightly used MongoDB in the past and found the MongoDB documentation data modeling to be a great starting point. The approach that you describe, storing a reference in the parent and using a second find to get the referenced items, is a perfectly good way to go about it, if you choose to make use of references rather than directly embedding the children in the parent object.

However, there might be some better ways to go at this. I have been looking into using Mongoose as an Object Document Mapper (ODM). It is the officially supported ODM for Node per the MongoDB documentation.

It provides a number of useful features, particularly if you are building a fairly complex model within the application, including pseudo-joins using the populate function. The population capability provides a more structured approach to managing references allowing for retrieval of parent and children in one step.

Elastic search is a search index that looks like a db and mongo is a database with decent search capabilities too.

I think the determinant should be your familiarity with the systems actually and if this is a greenfield project where you're diving into new technologies, you can minimize risk by using a more familiar technology like SQL instead of Mongo.

If you do go the mongo + elastic search route, my only other advice would be to NOT try to use the mongo db river, and insert and update into elastic search using the regular old rest api.