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/*
* Copyright (c) 2016-2023 Martin Donath <martin.donath@squidfunk.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
import {
Observable,
Subject,
endWith,
fromEvent,
ignoreElements,
mergeWith,
share,
takeUntil
} from "rxjs"
/* ----------------------------------------------------------------------------
* Types
* ------------------------------------------------------------------------- */
/**
* Worker message
*/
export interface WorkerMessage {
type: unknown /* Message type */
data?: unknown /* Message data */
}
/* ----------------------------------------------------------------------------
* Helper functions
* ------------------------------------------------------------------------- */
/**
* Create an observable for receiving from a web worker
*
* @template T - Data type
*
* @param worker - Web worker
*
* @returns Message observable
*/
function recv<T>(worker: Worker): Observable<T> {
return fromEvent<MessageEvent<T>, T>(worker, "message", ev => ev.data)
}
/**
* Create a subject for sending to a web worker
*
* @template T - Data type
*
* @param worker - Web worker
*
* @returns Message subject
*/
function send<T>(worker: Worker): Subject<T> {
const send$ = new Subject<T>()
send$.subscribe(data => worker.postMessage(data))
/* Return message subject */
return send$
}
/* ----------------------------------------------------------------------------
* Functions
* ------------------------------------------------------------------------- */
/**
* Create a bidirectional communication channel to a web worker
*
* @template T - Data type
*
* @param url - Worker URL
* @param worker - Worker
*
* @returns Worker subject
*/
export function watchWorker<T extends WorkerMessage>(
url: string, worker = new Worker(url)
): Subject<T> {
const recv$ = recv<T>(worker)
const send$ = send<T>(worker)
/* Create worker subject and forward messages */
const worker$ = new Subject<T>()
worker$.subscribe(send$)
/* Return worker subject */
const done$ = send$.pipe(ignoreElements(), endWith(true))
return worker$
.pipe(
ignoreElements(),
mergeWith(recv$.pipe(takeUntil(done$))),
share()
) as Subject<T>
}
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