@ng-web-apis/workers/fesm2022/ng-web-apis-workers.mjs

A library for comfortable use of Web Workers API in Angular

import { Observable, EMPTY, merge, fromEvent, tap, takeUntil, Subject, take, map } from 'rxjs';
import * as i0 from '@angular/core';
import { Pipe } from '@angular/core';

// throw an error using the `setTimeout` function
// because web worker doesn't emit ErrorEvent from promises
const WORKER_BLANK_FN = `
function(fn){
    function isFunction(type){
        return type === 'function';
    }

    self.addEventListener('message', function(e) {
        var result = fn.call(null, e.data);
        if (result && [typeof result.then, typeof result.catch].every(isFunction)){
            result
                .then(postMessage)
                .catch(function(error) {
                    setTimeout(function(){throw error}, 0)
                })
        } else {
            postMessage(result);
        }
    })
}
`;

class WebWorker extends Observable {
    worker;
    url;
    destroy$;
    constructor(url, options) {
        let worker;
        let error;
        try {
            worker = new Worker(url, options);
        }
        catch (e) {
            error = e;
        }
        super((subscriber) => {
            let eventStream$ = EMPTY;
            if (error) {
                subscriber.error(error);
            }
            else if (this.destroy$.isStopped) {
                subscriber.complete();
            }
            else if (worker) {
                eventStream$ = merge(fromEvent(worker, 'message').pipe(tap((event) => subscriber.next(event))), fromEvent(worker, 'error').pipe(tap((event) => subscriber.error(event)))).pipe(takeUntil(this.destroy$));
            }
            eventStream$.subscribe().add(subscriber);
        });
        this.worker = worker;
        this.url = url;
        this.destroy$ = new Subject();
    }
    static fromFunction(fn, options) {
        return new WebWorker(WebWorker.createFnUrl(fn), options);
    }
    static async execute(fn, data) {
        const worker = WebWorker.fromFunction(fn);
        // eslint-disable-next-line rxjs/no-topromise
        const promise = worker.pipe(take(1)).toPromise();
        worker.postMessage(data);
        return promise.then((result) => {
            worker.terminate();
            return result;
        });
    }
    static createFnUrl(fn) {
        const script = `(${WORKER_BLANK_FN})(${fn});`;
        const blob = new Blob([script], { type: 'text/javascript' });
        return URL.createObjectURL(blob);
    }
    terminate() {
        if (this.destroy$.isStopped) {
            return;
        }
        if (this.worker) {
            this.worker.terminate();
        }
        URL.revokeObjectURL(this.url);
        this.destroy$.next();
        this.destroy$.complete();
    }
    postMessage(value) {
        if (this.worker) {
            this.worker.postMessage(value);
        }
    }
}

function toData() {
    return map(({ data }) => data);
}

class WorkerPipe {
    fn;
    worker;
    observer;
    transform(value, fn) {
        if (this.fn !== fn) {
            this.terminateWorker();
            this.initNewWorker(fn);
        }
        this.worker.postMessage(value);
        return this.observer;
    }
    ngOnDestroy() {
        this.terminateWorker();
    }
    terminateWorker() {
        if (this.worker) {
            this.worker.terminate();
        }
    }
    initNewWorker(fn) {
        this.fn = fn;
        this.worker = WebWorker.fromFunction(fn);
        this.observer = this.worker.pipe(toData());
    }
    static ɵfac = i0.ɵɵngDeclareFactory({ minVersion: "12.0.0", version: "16.2.12", ngImport: i0, type: WorkerPipe, deps: [], target: i0.ɵɵFactoryTarget.Pipe });
    static ɵpipe = i0.ɵɵngDeclarePipe({ minVersion: "14.0.0", version: "16.2.12", ngImport: i0, type: WorkerPipe, isStandalone: true, name: "waWorker" });
}
i0.ɵɵngDeclareClassMetadata({ minVersion: "12.0.0", version: "16.2.12", ngImport: i0, type: WorkerPipe, decorators: [{
            type: Pipe,
            args: [{
                    standalone: true,
                    name: 'waWorker',
                }]
        }] });

/**
 * Generated bundle index. Do not edit.
 */

export { WebWorker, WorkerPipe, toData };
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