WarsawJS Meetup #133 - onsite

# WarsawJS Meetup #133 - You’re invited!

Date: 9th December 2025

Time: 18:30–21:30

Location:

DataArt Warsaw, WeWork, Mennica Legacy Tower, West Building, 1st floor, Room 01C

ul. Prosta 20

00-850 Warszawa

What to expect?

Daniil Volosyuk - AI app builder - deep dive

Daniil will speak about Monday Vibe - AI app builder. What value it brings to customers. How this product works under the hood, the most important technical concepts. Challenges and problems we had during development.

Szymon Chmal - Write Once, Test Everywhere: Cross-Platform Testing for React Native

Testing React Native apps has always been a trade-off between speed and realism. Jest is fast, familiar, and excellent for unit tests, but it runs in Node.js and relies on mocks for native modules. End-to-end frameworks offer realism, but at the cost of complex setup, ongoing maintenance, and slower pipelines. Enter React Native Harness, a new testing framework that lets you run Jest-style tests directly on real devices and simulators, with full access to native modules and no mocks by default.

Anton Morozov - State of Package Managers

In that talk, we will dive deep into npm, pnpm and bun package managers. We will see all the strengths and weaknesses of each of them. We will see possible ways to migrate, and we will dive into the code and run some metrics

Sponsors: Xfaang | DataArt

Media partner: K MAG

Partner: JetBrains, Webellian