Getting started

Audience: package users installing react-native-nitro-h3 for the first time. This page takes you from an empty project to a first cell: install, one call, and the requirements the build has to meet.

Installation

bun

1. Add the package together with Nitro Modules.

   bun add react-native-nitro-h3 react-native-nitro-modules

2. Install the iOS pods.

   cd ios && pod install

3. Rebuild the app so the native module is linked, with npx react-native run-ios or npx react-native run-android.

npm

1. Add the package together with Nitro Modules.

   npm install react-native-nitro-h3 react-native-nitro-modules

2. Install the iOS pods.

   cd ios && pod install

3. Rebuild the app so the native module is linked, with npx react-native run-ios or npx react-native run-android.

Expo

1. Add the package with the Expo CLI.

   npx expo install react-native-nitro-h3 react-native-nitro-modules

2. Generate the native projects.

   npx expo prebuild

   Expo Go cannot load native modules. Use a development build with npx expo run:ios or npx expo run:android.

First call

import {
  latLngToCell,
  gridDisk,
  cellToString,
} from 'react-native-nitro-h3'

// H3 cell for San Francisco at resolution 9
const cell = latLngToCell(37.7749, -122.4194, 9)

// Get neighboring cells
const neighbours = gridDisk(cell, 1)

console.log(neighbours.length) // 7
console.log(cellToString(cell)) // "89283082803ffff"

latLngToCell returns a bigint, and gridDisk returns a BigUint64Array. Both are explained in Cell indexes and bigint.

Requirements

Platform	Requirement
React Native	0.76+
Nitro Modules	0.37.0 or newer
C++	C++20-compatible toolchain
iOS	React Native deployment target
Xcode	recent stable release
Android	minSdk 24
Android SDK	compileSdk 36
Android NDK	27.1.12297006
H3 C library	4.5.0, vendored

The package requires the New Architecture, the default since React Native 0.76. The iOS and Android build workflows compile the example app against React Native 0.87.0.

Next steps

• Migrating from h3-js if you are replacing h3-js.
• Typed arrays and batch calls for workloads over many cells.
• API reference for every exported function.