Trouble with posting JSON data (with node request) to Express server for saving into MongoDB

I use MongoDB as the back-end database for my node/Express application. To summarize the problem I am facing, I don’t know how to set up the body-parser configuration in my Express app, because the server side application is not receiving the full JSON posted by the client application (also a node.js app). For the most part, the client is sending JSON in the request body to RESTful endpoints. The exception being a single case where a file needs to be uploaded and since that is a multipart body, I am using request and form-data to build that type of request and using multer on the server side to process the multipart request, since body-parser does not process such requests.