When attempting to import classes from files that import additional classes in Angular 8 with WebWorker, compilation errors arise

Currently in Angular v8 and encountering an issue with my model.ts file structure, which includes the following code:

import {map} from 'rxjs/operators';

export class Person {
 constructor() { }
}

In addition, I have a WebWorker file called test.worker.ts with the following content:

/// <reference lib="webworker" />
import {Person} from './bo/model';

addEventListener('message', ({ data }) => {
  const response = `worker response to ${data}`;
  postMessage(response);
});

An error is triggered when running ng compile, specifically related to the import statement

import {map} from 'rxjs/operators'
. This leads to a TS2339 error regarding property 'observable' not existing on type 'SymbolConstructor.'

Upon commenting out the troublesome import and including

import {HttpClient} from '@angular/common/http';
, a different set of errors arise, such as those related to missing names like 'Element' and 'Node'.

Surprisingly, importing

import {Observable, of} from 'rxjs';
results in no errors at all. The conflicting behaviors raise questions about the limitations on importing libraries within Angular applications, especially when it comes to dependencies.

Please note that this scenario takes place within ng-cli version 8.0.2.

Answer №1

Although I am uncertain about the problem related to the rxjs/operators import, there is a clear issue with importing HttpClient.

The underlying complication lies in the fact that Web Workers are unable to interact with the DOM (). Therefore, using @angular/common, which accesses the DOM, is not allowed. I am facing a similar challenge as I attempt to utilize pipes within my worker, which rely on imports from @angular/common. This situation can be quite frustrating as the methods and classes of @angular/common that I require have no direct association with the DOM. Thus far, the only potential resolution I have come across is performing any necessary DOM manipulation outside of the worker (if feasible).

TL;DR: It is not viable to access or utilize libraries that interact with the DOM within the web worker. These actions should ideally occur externally to ensure proper functionality.

edit: To provide further clarification, it is not simply a matter of web workers being unable to access the DOM, but rather they cannot have access to the DOM for purposes of thread safety. () and (https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Using_web_workers#about_thread_safety).

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