feat(QueryCursor): add getDriverCursor() function that returns the raw driver cursor

lib/cursor/queryCursor.js

@@ -10,6 +10,7 @@ const eachAsync = require('../helpers/cursor/eachAsync');
 const helpers = require('../queryHelpers');
 const kareem = require('kareem');
 const immediate = require('../helpers/immediate');
+const { once } = require('node:events');
 const util = require('util');
 
 /**
@@ -135,6 +136,25 @@ QueryCursor.prototype._read = function() {
  });
 };
 
+/**
+ * Returns the underlying cursor from the MongoDB Node driver that this cursor uses.
+ *
+ * @method getDriverCursor
+ * @memberOf QueryCursor
+ * @returns {Cursor} MongoDB Node driver cursor instance
+ * @instance
+ * @api public
+ */
+
+QueryCursor.prototype.getDriverCursor = async function getDriverCursor() {
+ if (this.cursor) {
+ return this.cursor;
+ }
+
+ await once(this, 'cursor');
+ return this.cursor;
+};
+
 /**
  * Registers a transform function which subsequently maps documents retrieved
  * via the streams interface or `.next()`

test/query.cursor.test.js

@@ -900,6 +900,25 @@ describe('QueryCursor', function() {
  assert.ok(err);
  assert.ok(err.message.includes('skipMiddlewareFunction'), err.message);
  });
+
+ it('returns the underlying Node driver cursor with getDriverCursor()', async function() {
+ const schema = new mongoose.Schema({ name: String });
+
+ const Movie = db.model('Movie', schema);
+
+ await Movie.deleteMany({});
+ await Movie.create([
+ { name: 'Kickboxer' },
+ { name: 'Ip Man' },
+ { name: 'Enter the Dragon' }
+ ]);
+
+ const cursor = await Movie.find({}).cursor();
+ assert.ok(!cursor.cursor);
+ const driverCursor = await cursor.getDriverCursor();
+ assert.ok(cursor.cursor);
+ assert.equal(driverCursor, cursor.cursor);
+ });
 });
 
 async function delay(ms) {