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To cause the cursor of the MongoDB-NodeJS driver to generate data in the form of a string/buffer stream instead of an object stream, you can use the stream() method on the cursor object.

Here's an example:

const MongoClient = require('mongodb').MongoClient;

MongoClient.connect('mongodb://localhost:27017/test', function(err, client) {
  if (err) throw err;

  const db = client.db('test');
  const collection = db.collection('mycollection');

  const stream = collection.find().stream({
    transform: function(doc) {
      return JSON.stringify(doc) + '\n';
    }
  });

  stream.on('data', function(chunk) {
    console.log(chunk);
  });

  stream.on('error', function(err) {
    console.error(err);
  });

  stream.on('end', function() {
    console.log('Done!');
  });
});

In this example, we're using the stream() method on the result of the find() operation to create a cursor that generates a stream of objects. We've passed an option object to the stream() method with a transform function that converts the objects to JSON strings with a newline character.

Then, we listen for the 'data' event on the resulting stream and log each chunk of data to the console. We also listen for 'error' and 'end' events to handle any errors and signal when the stream has ended.