@frostbyte-os/react-native-escpos

React Native network adapter for ESC/POS receipt printers. Opens a raw TCP socket to a network printer and writes ESC/POS byte sequences to it.

Node's net module does not exist in React Native, so this wraps react-native-tcp-socket behind the same adapter shape the escpos ecosystem expects.

Install

npm install @frostbyte-os/react-native-escpos react-native-tcp-socket

react-native-tcp-socket is a peer dependency, so you install it yourself. Follow its own setup steps for the native side, including the Android INTERNET permission and a pod install for iOS.

Usage

import Network from "@frostbyte-os/react-native-escpos";

const printer = new Network("192.168.1.50", 9100);

printer.open((err) => {
  if (err) {
    console.warn("printer unreachable", err);
    return;
  }

  // ESC @ = initialize, then text, then GS V 0 = full cut
  printer.write(Buffer.from([0x1b, 0x40]));
  printer.write(Buffer.from("Hello world\n", "ascii"));
  printer.write(Buffer.from([0x1d, 0x56, 0x00]), () => {
    printer.close();
  });
});

Most network receipt printers listen on TCP 9100, which is the default when you omit the port.

API

new Network(address, [port])

Creates an adapter. port defaults to 9100. Does not connect; call open() for that.

.open(callback, [params])

Opens the socket. callback(err, device) fires on connect, and again with an error if the socket errors. params.onSocketKill(device) is invoked when the socket errors out.

.write(data, [callback])

Writes bytes to the printer. data is a Buffer, Uint8Array, or string. callback fires once the bytes are flushed.

.read(callback)

Subscribes to inbound data, callback(buffer) per chunk. Useful for real-time status back from printers that support it.

.close([callback])

Destroys the socket and emits disconnect. callback(null, device) fires afterward.

Events

Network extends EventEmitter and emits disconnect when close() runs.

Known issues

isConnected is defined both as an instance boolean and as a prototype method, and the boolean wins. Read it as a property (printer.isConnected) rather than calling it, since printer.isConnected() throws.

License

MIT