JavaScript API

Everything is exported from tauri-plugin-serialplugin-api:

import {
  SerialPort,
  DataBits, FlowControl, Parity, StopBits, ClearBuffer, LogLevel,
} from "tauri-plugin-serialplugin-api";

All methods return promises that reject with a string message on failure (see Errors).

AT commands, exchange(), SMS and CMUX have their own page: AT commands, exchange and CMUX.

Creating a port

const port = new SerialPort({
  path: "/dev/ttyUSB0",   // COM3, /dev/cu.usbserial-…, tcp://host:port, ble://<id>
  baudRate: 115200,
});

Discovery (static)

PortInfo is { type, vid, pid, manufacturer, product, serial_number }; unknown fields are "Unknown". On macOS every device appears twice (/dev/cu.* and /dev/tty.*); singlePortPerDevice: true keeps the cu.* one.

const stop = await SerialPort.watchAvailablePorts({
  onSnapshot: (ports) => console.log(Object.keys(ports)),
  onAdded: (path, info) => console.log("plugged", path, info.product),
  onRemoved: (path) => console.log("unplugged", path),
}, { singlePortPerDevice: true });
// later
await stop.unwatch();

Open and close

Streaming with watch()

watch() delivers incoming data, unsolicited AT lines, errors and disconnects through one Tauri channel. One watch per port at a time.

const handle = await port.watch({
  onData: (data) => console.log(data),          // string (decoded) or Uint8Array
  onUrc: (line) => console.log("URC", line),    // optional, AT modems
  onError: (message) => console.warn(message),  // non-fatal
  onDisconnect: (reason) => console.log(reason) // port is gone
}, { decode: true });

await handle.unwatch();

activeWatch returns the current handle (or null).

Reading and writing

read() / readBinary() wait up to timeout for data and reject with no data received within … ms if nothing arrives. They cannot run while a watch() is active — use one model per port: polling reads or a watch.

For request/response protocols use exchange() / sendAt(): they write, wait for the reply and keep concurrent calls in order.

Line settings

setBaudRate(n), setDataBits(DataBits), setParity(Parity), setStopBits(StopBits), setFlowControl(FlowControl), setTimeout(ms).

The new value is also kept in port.options, so a reconnect or change() reopens with it. Over tcp:// and ble:// these are stored only (the bridge or radio owns the real line settings).

Modem lines and buffers

Auto-reconnect

port.enableAutoReconnect({
  interval: 3000,        // ms between attempts (fixed, no backoff)
  maxAttempts: 10,       // null = forever
  onReconnect: (ok, attempt) => console.log(ok ? `back after ${attempt}` : `attempt ${attempt} failed`),
});
await port.watch({ onData: console.log });

After onDisconnect the port is reopened and the last watch is re-established with the same handlers. disableAutoReconnect() stops it, getAutoReconnectInfo() reports { enabled, interval, maxAttempts, currentAttempts, hasCallback }, and manualReconnect() tries once now. close() also cancels a pending reconnect.

Logging

await SerialPort.setLogLevel(import.meta.env.DEV ? LogLevel.Debug : LogLevel.Error);
const level = await SerialPort.getLogLevel();

Levels: None, Error, Warn, Info (default), Debug. The level applies to the native side and to the JS wrapper.

Enums

Option and result types (SerialportOptions, WatchOptions, WatchHandlers, WatchHandle, PortInfo, ExchangeOptions, ExchangeResponse, AtCommandOptions, AtCommandResult, AtSessionOptions, Capabilities, …) are exported too; see the types reference, generated from guest-js/types.ts.

Errors

Other failures carry the OS / driver text unchanged.