
Kræn Hansen
Kræn is a Senior Software Engineer at MongoDB contributing primarily to Compass, MongoDB Shell, Realm JS and its related packages. He has build and maintained multiple React apps, including the Realm Cloud (replaced by MongoDB Atlas post acquisition) and Realm Studio (an Electron app to browse the Realm database). He lives 30 minutes west of Copenhagen, with his wife and their two twin girls and 2-yo baby girl.
Rusty Native Modules for React Native
React Summit 2025

Upcoming
Rusty Native Modules for React Native

It’s now easier than ever to build and maintain Rust libraries for React Native - and I’ll show you how.I want to tell you the story of how we got here in the first place, motivate the benefits of Rust libraries in React Native, explain the difficulties of interoperating across native languages and show how the introduction of the NAPI binding in Hermes and the new Ferric build tool, brings the missing pieces for automatically generating performant type-safe prebuilt bindings of Rust libraries.My ultimate goal of this talk is to inspire you to build with Rust in your next React Native project.
Building C++ / JSI Native Modules for React Native in 2024
React Summit US 2024Watch video: Building C++ / JSI Native Modules for React Native in 2024

17 min
Building C++ / JSI Native Modules for React Native in 2024

Building C++ modules for React Native is easier than you might think (if you know how). In this talk I’ll be sharing the current state best practices on bootstrapping of native C++ modules for React Native!
How Realm by MongoDB is Testing Native Modules “on device”
React Summit US 2023Watch video: How Realm by MongoDB is Testing Native Modules “on device”

11 min
How Realm by MongoDB is Testing Native Modules “on device”

Running tests on Node.js is common practice for app and library developers. But when your library is integrating more deeply with the platform, operating system or JS engine, you need to run tests “on device” increases. The Realm JS team at MongoDB is faced with this challenge, as we’re maintaining a React Native library with native modules. In this talk I’ll share the “mocha-remote” package which we’ve built to help us run tests “on device” while getting reporting and remaining in control from the comfort of our terminals.