/// <reference types="w3c-web-serial" />
/**
 * @packageDocumentation
 * @module Utility
 */
import { Observable } from 'rxjs';
/**
 * Returns an Observable that emits the response from a source connected to via the
 * {@link https://reillyeon.github.io/serial|Web Serial API}. The function can also accept an Observable
 * that emits values to write to the serial device, allowing two-way communication.
 *
 * Both the input and output values must be
 * {@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array|Uint8Array}, you
 * can use {@link https://developer.mozilla.org/en-us/docs/Web/API/TextEncoder|TextEncoder} and
 * {@link https://developer.mozilla.org/en-US/docs/Web/API/TextDecoder|TextDecoder} to convert between strings, which
 * can  be seen in the demo
 *
 * The function will also handle opening and closing of the port from the serial device when using an `AbortSignal` or
 * ending the RxJS subscription.
 *
 * @category Streams
 *
 * @remarks Web Serial is available in Chrome or Edge 89 or later, in earlier versions it can be enabled using the
 *   experimental web features flag. To use the feature is **must** be invoked with a user action such as a user
 *   button click, and in a browser location that provides an acceptable policy before the port can be opened by this
 *   operator.
 *
 * @see {@link https://rxjs-from-web-serial.stackblitz.io|RxJS Web Serial Demo}
 * @see {@link https://stackblitz.com/edit/rxjs-from-web-serial|Demo Source}
 *
 * @param port The SerialPort object to connect to
 * @param writerSource Optional Observable source to emit values to the serial connection writer
 * @param options Options for the connection - if none passed a default `baudRate` of `9600` is set
 * @param signal Optional signal to end the source
 *
 * @returns Observable that emits the output from a serial source
 */
export declare function fromWebSerial(port: SerialPort, writerSource?: Observable<Uint8Array>, options?: SerialOptions, signal?: AbortSignal): Observable<Uint8Array>;