'use strict' ; const runTest = async () => { const MongoClient = require( 'mongodb' ).MongoClient; let client; let db; let s1, s2; try { console.log( 'Creating database' ); client = await MongoClient.connect( 'mongodb: //localhost:27017' ); db = client.db( 'testdb' ); await db.dropDatabase(); let collection = await db.createCollection( 'testcoll' ); await db.createIndex( 'testcoll' , \{id: 1}, \{unique: true }); await db.createIndex( 'testcoll' , \{prop1: 1}, \{unique: true , partialFilterExpression: {prop1: {$exists: true }}}); console.log( 'Inserting documents' ); s1 = client.startSession(); s1.startTransaction(); s2 = client.startSession(); s2.startTransaction(); await collection.insertOne(\{id:1}, \{session: s1}); await collection.insertOne(\{id:2}, \{session: s2}); await s1.commitTransaction(); await s2.commitTransaction(); await s1.endSession(); await s2.endSession(); console.log( 'Deleting documents' ); s1 = client.startSession(); s1.startTransaction(); s2 = client.startSession(); s2.startTransaction(); await collection.deleteOne(\{id:1}, \{session: s1}); await collection.deleteOne(\{id:2}, \{session: s2}); await s1.commitTransaction(); await s2.commitTransaction(); await s1.endSession(); await s2.endSession(); } catch (error) { if (s1 && s1.inTransaction()) { await s1.abortTransaction(); s1.endSession(); } if (s2 && s2.inTransaction()) { await s2.abortTransaction(); s2.endSession(); } throw error; } }; runTest() .then (() => { process.exit(0); }) . catch (err => { console.error(err); process.exit(1); });