Query when using .stream() method does not understand Strings as ObjectIDs or Dates

When running a find() and then stream() as per below

Model.find({
 "_id":{
     "$in":["5aa8f1226744783cd807a817"]
 },
 "date":{
    "$gte":"2019-08-14T23:38:17.123Z"
  }
})
.lean()
.batchSize(100)
.stream();

Mongoose does not cast the “5aa8f1226744783cd807a817” as an ObjectID, neither does it cast “2019-08-14T23:38:17.123Z” as a Date, it runs the query with those values typed as a String and doesn’t return match the records from the database.

However running the same query with the .exec() method works correctly.

Model.find({
 "_id":{
     "$in":["5aa8f1226744783cd807a817"...]
 },
"date":{
    "$gte":"2019-08-14T23:38:17.123Z"
  }
})
.lean()
.exec(function(err, docs) {

});

This has only been an issue since we upgraded to a recent version of Mongoose

[vkarpov15]

Which version of mongoose did you upgrade to? stream() is no longer supported, it’s been replaced by cursor() : https://thecodebarbarian.com/cursors-in-mongoose-45

[vkarpov15]

I’m unable to find any indication that cursor() is orders of magnitude slower than stream(). Consider the below script:

'use strict';

const mongoose = require('mongoose');

run().catch(err => console.log(err));

async function run() {
  await mongoose.connect('mongodb://localhost:27017/test');
  await mongoose.connection.dropDatabase();

  const Model = mongoose.model('Test', mongoose.Schema({ name: String }));
  for (let i = 0; i < 10000; ++i) {
    let name = '' + i;
    for (let i = 0; i < 100; ++i) { name += 'a' }
    await Model.create({ name });
  }

  const startTime = Date.now();
  //const cursor = Model.find().lean().batchSize(1000).stream();
  const cursor = Model.find().lean().batchSize(1000).cursor();
  let count = 0;

  await new Promise(resolve => {
    cursor.on('data', () => ++count);
    cursor.on('end', () => resolve());
  });
  console.log('Time elapsed:', Date.now() - startTime);
  console.log('Num docs:', count);
}

Mongoose 5.7 using cursor():

$ node gh-8039.js 
(node:1288) DeprecationWarning: current URL string parser is deprecated, and will be removed in a future version. To use the new parser, pass option { useNewUrlParser: true } to MongoClient.connect.
(node:1288) DeprecationWarning: current Server Discovery and Monitoring engine is deprecated, and will be removed in a future version. To use the new Server Discover and Monitoring engine, pass option { useUnifiedTopology: true } to the MongoClient constructor.
Time elapsed: 96
Num docs: 10000
^C
$ 

Mongoose 4.13 using stream():

$ node gh-8039.js 
(node:1285) DeprecationWarning: `open()` is deprecated in mongoose >= 4.11.0, use `openUri()` instead, or set the `useMongoClient` option if using `connect()` or `createConnection()`. See http://mongoosejs.com/docs/4.x/docs/connections.html#use-mongo-client
(node:1285) DeprecationWarning: Mongoose: mpromise (mongoose's default promise library) is deprecated, plug in your own promise library instead: http://mongoosejs.com/docs/promises.html
(node:1285) DeprecationWarning: Mongoose: Query.prototype.stream() is deprecated in mongoose >= 4.5.0, use Query.prototype.cursor() instead
Time elapsed: 77
Num docs: 10000
^C
$

How are you iterating through the stream?