Files
mkdocs-material/src/assets/javascripts/browser/worker/index.ts

105 lines
3.3 KiB
TypeScript

/*
* Copyright (c) 2016-2020 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, fromEvent } from "rxjs"
import {
map,
share,
switchMapTo,
tap,
throttle
} from "rxjs/operators"
/* ----------------------------------------------------------------------------
* Types
* ------------------------------------------------------------------------- */
/**
* Worker message
*/
export interface WorkerMessage {
type: unknown /* Message type */
data?: unknown /* Message data */
}
/**
* Worker handler
*
* @template T - Message type
*/
export interface WorkerHandler<
T extends WorkerMessage
> {
tx$: Subject<T> /* Message transmission subject */
rx$: Observable<T> /* Message receive observable */
}
/* ----------------------------------------------------------------------------
* Helper types
* ------------------------------------------------------------------------- */
/**
* Watch options
*
* @template T - Worker message type
*/
interface WatchOptions<T extends WorkerMessage> {
tx$: Observable<T> /* Message transmission observable */
}
/* ----------------------------------------------------------------------------
* Functions
* ------------------------------------------------------------------------- */
/**
* Watch a web worker
*
* This function returns an observable that will send all values emitted by the
* message observable to the web worker. Web worker communication is expected
* to be bidirectional (request-response) and synchronous. Messages that are
* emitted during a pending request are throttled, the last one is emitted.
*
* @param worker - Web worker
* @param options - Options
*
* @returns Worker message observable
*/
export function watchWorker<T extends WorkerMessage>(
worker: Worker, { tx$ }: WatchOptions<T>
): Observable<T> {
/* Intercept messages from worker-like objects */
const rx$ = fromEvent<MessageEvent>(worker, "message")
.pipe(
map(({ data }) => data as T)
)
/* Send and receive messages, return hot observable */
return tx$
.pipe(
throttle(() => rx$, { leading: true, trailing: true }),
tap(message => worker.postMessage(message)),
switchMapTo(rx$),
share()
)
}