Configuration (nitro.json)

Nitrogen requires a nitro.json file to be configured at the root of each Nitro Module.

{
  "$schema": "https://nitro.margelo.com/nitro.schema.json",
  "environment": "react-native",
  "cxxNamespace": ["$$cxxNamespace$$"],
  "apple": {
    "moduleName": "$$appleModuleName$$"
  },
  "android": {
    "namespace": ["$$androidNamespace$$"],
    "cxxLibName": "$$androidCxxLibName$$"
  },
  "ignorePaths": ["**/node_modules"]
}

Nitrogen parses this file with Zod, see NitroUserConfig.ts for more information.

environment

Selects the package that generated JavaScript code imports Nitro APIs from:

• "react-native" (default): imports from react-native-nitro-modules, which installs Nitro in the React Native runtime.
• "bare": imports from nitro-core for standalone runtimes.

This setting only changes the JavaScript imports. Native code generation is the same for both environments.

cxxNamespace

The cxxNamespace is the C++ namespace that all C++ specs will be generated in. It is always relative to margelo::nitro, and can also have multiple sub-namespaces:

{
  "cxxNamespace": ["math", "extra"]
}

namespace margelo::nitro::math::extra {
  // ...generated classes
}

apple

Settings for the Apple platforms: iOS, macOS, tvOS and visionOS.

moduleName

The moduleName names the generated Swift module for CocoaPods and Swift Package Manager, and the SwiftPM library product. Libraries that support SwiftPM must use the same name in swiftpmConfig:

{
  "apple": {
    "moduleName": "NitroMath"
  }
}

package.json

{
  "swiftpmConfig": {
    "name": "NitroMath",
    "dependencies": ["react-native-nitro-modules"]
  }
}

See Nitrogen's build setup for CocoaPods, Package.swift and generated source configuration.

android

Settings specifically for the Android platform.

namespace

The namespace represents the package namespace in which all Java/Kotlin files are generated and written in. Similar to the cxxNamespace, this is always relative to com.margelo.nitro, and can also have multiple sub-namespaces.

In most cases, keep it in sync with the namespace in your build.gradle, which holds the full package (com.margelo.nitro.math.extra).

{
  "android": {
    "namespace": ["math", "extra"]
  }
}

package com.margelo.nitro.math.extra

// ...

cxxLibName

The cxxLibName represents the name of the native C++ library that JNI will load to connect Java/Kotlin to C++.

When this Nitro Module is using CMake, this is the same thing as the library defined in CMakeLists.txt. Nitro will load this library at runtime using System.loadLibrary.

{
  "android": {
    "cxxLibName": "NitroMath"
  }
}

project(NitroMath)
add_library(NitroMath SHARED
        src/main/cpp/cpp-adapter.cpp
        ../cpp/HybridMath.cpp
)

ignorePaths

Configures the TypeScript parser to ignore specific given paths when looking for *.nitro.ts specs.

By default, this is empty ([]), but it can be set to ignore paths like ["node_modules", "lib"].