Windows

Windows

The package supports React Native Windows 0.84+ with the New Architecture
(Fabric / WinAppSDK, cpp-app template). The JS API and the C++ protocol core
are the same as on iOS and Android. Only the TCP transport is Windows-specific.

Requirements

• Windows 10 22H2+ or Windows 11.
• Node.js 22.11 or newer.
• Visual Studio 2022 (MSVC v143) or 2026 (MSVC v145) with the “Desktop development with C++” and “Windows application development” workloads.
• Windows SDK 10.0.26100.
• react-native-windows 0.84+ and react-native-nitro-modules in the app.

RNW’s rnw-dependencies.ps1 script (in node_modules/react-native-windows/scripts) installs missing tools.

Setup

Install the package and Nitro:

npm install @padosoft/react-native-ecr17 react-native-nitro-modules

Add the Windows autolink helper to the app’s react-native.config.js:

const { windowsAppDependencies } = require("@padosoft/react-native-ecr17/windows-autolink");

module.exports = {
  dependencies: windowsAppDependencies(),
};

Link and build:

npx react-native autolink-windows
npx react-native run-windows

Client code is unchanged:

import { createEcr17Client } from "@padosoft/react-native-ecr17";

const client = createEcr17Client({
  host: "192.168.1.100",
  port: 10000,
  terminalId: "00000000",
  cashRegisterId: "00000001",
});

How it works

• Ecr17.dll implements NitroModules.install(). It runs Nitro’s install() with RNW’s JSI runtime and CallInvoker.
• Ecr17Client is the shared C++ HybridEcr17Client over the Kit’s Ecr17Client, the same code as on iOS and Android.
• Ecr17Transport is HybridEcr17TransportWindows, the Nitro face of the Kit’s C++ WinsockTransport (iOS uses Swift, Android uses Kotlin).
• The DLL compiles Nitro’s C++ runtime from the app’s node_modules/react-native-nitro-modules.
• Before compiling, MSBuild runs scripts/windows-nitro-shims.mjs, which writes <NitroModules/…> header shims because MSVC has no header map.

Only one native module per app can provide the NitroModules TurboModule. Another Nitro library that ships the same shim would conflict.

Payment safety on Windows

The Winsock transport keeps the same contract as the Kotlin one:

• isConnected() is a write-free, non-destructive probe (an instant select poll plus recv with MSG_PEEK). A socket the terminal closed between transactions is detected before a command is sent, so the client reconnects first.
• The probe never writes to the terminal and never consumes a protocol byte.
• onDisconnect fires once per unexpected drop and never for a caller’s disconnect().

Example app and tests

example-windows/ in the repository is a small RNW console app (status, totals, last result, one payment). It is a separate npm project, because RNW 0.84 pins React Native 0.84.1 while the Expo example uses a newer React Native.

The Kit’s tests (cmake -S kit) run the Winsock transport against a loopback server on Windows, with no Nitro or React Native Windows needed: drop detected before send, no bytes written by the probe, none consumed, one disconnect signal per drop, and a fast probe. Windows has no CI job, so run it and the example-windows build locally after native changes.

Status

The Windows build, the transport tests and a runtime smoke test are verified locally. The smoke test ran in the deployed example app against a fake terminal: Nitro installed, the client connected, a status frame went out, and the drop was detected after the terminal closed the socket. The integration has not been verified against a physical terminal yet. Test with small amounts on a test terminal before production use.