React Native Nitro Geolocation
Guide
Guide

Why Nitro Module?

The Nitro Module system provides the next generation of native modules for React Native. Instead of using the bridge-based approach (JSON serialization between JS and native), Nitro Modules communicate directly through JSI (JavaScript Interface).

This enables:

  • ⚡ Direct native calls — reduced overhead
  • 🧠 Synchronous APIs for critical paths
  • 🔧 Better integration with the new Fabric renderer
  • 🧩 Cross-platform consistency and simpler maintenance

In short, Nitro Geolocation builds on the proven API design of @react-native-community/geolocation while leveraging the new React Native architecture, providing a forward-compatible foundation with 100% API compatibility.

Architecture Comparison

Origin: Event-based Architecture (@react-native-community/geolocation)

JavaScript Layer ↓ EventEmitter.addListener('geolocationDidChange', callback) ↓ (Callback stored in JS only) React Native Bridge (JSON serialization) ↓ Native Layer (Android/iOS) ↓ LocationListener receives updates ↓ emit('geolocationDidChange', data) → Bridge ↓ EventEmitter dispatches to all listeners ↓ User callback executed

Key characteristics:

  • Callbacks not passed to native — stored in JS EventEmitter
  • Native emits generic events through Bridge
  • Multiple listeners share one event stream
  • Requires JSON serialization on every update

Modern: Direct Callback Architecture (React Native Nitro Geolocation)

JavaScript Layer ↓ nitroGeolocation.watchPosition(success, error, options) ↓ (Callbacks passed directly to native via JSI) JSI Layer (No Bridge!) ↓ Native Layer (Kotlin/Swift) ↓ LocationListener receives updates ↓ callback.success(position) → JSI direct call ↓ User callback executed immediately

Key characteristics:

  • Callbacks passed directly to native as JSI function references
  • Native calls JS functions directly (no Bridge)
  • Each watch has its own callback (no shared event stream)
  • Minimal serialization (C++ structs → JS objects)

How JSI Enables Direct Callbacks

Nitro Modules use Nitrogen code generation to create JSI bindings:

  1. TypeScript spec (NitroGeolocation.nitro.ts) defines the interface
  2. Nitrogen generates C++ code that bridges Kotlin/Swift ↔ JSI
  3. HybridObject in native code implements the spec
  4. JSI holds references to JS functions and calls them directly

Result: When watchPosition(callback) is called, the callback function becomes a JSI function reference in native code, callable without the Bridge.

When to Use Each Approach

Use Event-based if:

  • Supporting React Native < 0.68
  • Team unfamiliar with JSI/New Architecture
  • Stability over performance

Use Nitro (Direct Callback) if:

  • Performance-critical (real-time tracking, animations)
  • Using React Native New Architecture
  • Need type safety at compile-time
  • Building for the future

Summary

React Native Nitro Geolocation transforms the geolocation API from a Bridge-mediated event system to a JSI-powered direct callback system, delivering native-level performance while maintaining 100% API compatibility with the original library.

ON THIS PAGE