├── .gitignore
├── README.md
├── node-parent-thread-rxjs.js
├── node-worker-thread-rxjs.js
├── package-lock.json
└── package.json


/.gitignore:
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1 | /node_modules


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/README.md:
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1 | This repository contains a demonstration of the `worker_threads` module that is now standard in **Node 11.7.0**. To make things interesting, I am using **Rxjs** `Observable` stream messages from the worker thread.
2 | 
3 | This demo requires **Node 11.7.0** or higher.
4 | 
5 | To run the demo, run `npm install` then `npm start`.
6 | 
7 | 
8 | 
9 | 


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/node-parent-thread-rxjs.js:
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 1 | const Rxjs = require('rxjs');
 2 | const RxjsOperators = require('rxjs/operators');
 3 | const { Worker } = require('worker_threads');
 4 | 
 5 | console.log("\nNode multi-threading demo using worker_threads module in Node 11.7.0\n");
 6 | 
 7 | const COMPLETE_SIGNAL = 'COMPLETE';
 8 | 
 9 | function runTask(workerData, completedOnTime) {
10 |     return Rxjs.Observable.create(observer => {
11 |         const worker = new Worker('./node-worker-thread-rxjs.js', { workerData });
12 |         worker.on('message', message => observer.next(message));
13 |         worker.on('error', error => observer.error(error));
14 |         worker.on('exit', code => {
15 |             if (code !== 0) {
16 |                 observer.error(`Worker stopped with exit code ${code}`);
17 |             } else {
18 |                 completedOnTime();
19 |                 observer.next(COMPLETE_SIGNAL);
20 |                 observer.complete();
21 |             }
22 |         });
23 |     });
24 | }
25 | 
26 | const MAX_WAIT_TIME = 3;
27 | const WORKER_TIME = 10;
28 | 
29 | function main() {
30 |     completedOnTime = false;
31 | 
32 |     console.log(`[Main] Starting worker from process ${process.pid}`);
33 | 
34 |     const worker$ = runTask(WORKER_TIME, () => completedOnTime = true);
35 | 
36 |     // receive messages from worker until it completes but only wait for MAX_WAIT_TIME
37 |     worker$.pipe(
38 |         RxjsOperators.takeWhile(message => message !== COMPLETE_SIGNAL),
39 |         RxjsOperators.takeUntil(Rxjs.timer(MAX_WAIT_TIME * 1000))
40 |     ).subscribe(
41 |         result => console.log(`[Main] worker says: ${result}`),
42 |         error => console.error(`[Main] worker error: ${error}`),
43 |         () => {
44 |             if (!completedOnTime) {
45 |                 console.log(`[Main] worker could not complete its work in the allowed ${MAX_WAIT_TIME}s, exiting Node process`);
46 |                 process.exit(0);
47 |             } else {
48 |                 console.log(`[Main] worker completed its work in the allowed ${WORKER_TIME}s`);
49 |             }
50 |         }
51 |     );
52 | }
53 | 
54 | main();


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/node-worker-thread-rxjs.js:
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 1 | const { workerData, parentPort } = require('worker_threads');
 2 | 
 3 | parentPort.postMessage(`starting heavy duty work from process ${process.pid} that will take ${workerData}s to complete`);
 4 | 
 5 | timeLimit = workerData;
 6 | timer = 0;
 7 | 
 8 | // simulate a long-running process with updates posted back on a regular interval
 9 | do {
10 |     setTimeout(
11 |         (count) => {
12 |             parentPort.postMessage(`heavy duty work in progress...${count + 1}s`);
13 |             if (count === timeLimit) {
14 |                 parentPort.postMessage('done heavy duty work');
15 |             }
16 |         },
17 |         1000 * timer,
18 |         timer);
19 | } while (++timer !== timeLimit);
20 | 


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/package-lock.json:
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 1 | {
 2 |   "name": "node-worker-threads-demo",
 3 |   "version": "1.0.0",
 4 |   "lockfileVersion": 1,
 5 |   "requires": true,
 6 |   "dependencies": {
 7 |     "rxjs": {
 8 |       "version": "6.3.3",
 9 |       "resolved": "https://repo.dcts.tdbank.com:9443/content/groups/npm-all/rxjs/-/rxjs-6.3.3.tgz",
10 |       "integrity": "sha512-JTWmoY9tWCs7zvIk/CvRjhjGaOd+OVBM987mxFo+OW66cGpdKjZcpmc74ES1sB//7Kl/PAe8+wEakuhG4pcgOw==",
11 |       "requires": {
12 |         "tslib": "^1.9.0"
13 |       }
14 |     },
15 |     "tslib": {
16 |       "version": "1.9.3",
17 |       "resolved": "https://repo.dcts.tdbank.com:9443/content/groups/npm-all/tslib/-/tslib-1.9.3.tgz",
18 |       "integrity": "sha512-4krF8scpejhaOgqzBEcGM7yDIEfi0/8+8zDRZhNZZ2kjmHJ4hv3zCbQWxoJGz1iw5U0Jl0nma13xzHXcncMavQ=="
19 |     }
20 |   }
21 | }
22 | 


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/package.json:
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 1 | {
 2 |   "name": "node-worker-threads-demo",
 3 |   "version": "1.0.0",
 4 |   "description": "A demonstration of Node worker_threads module now available in Node 11.7.0 with Rxjs Observables.",
 5 |   "main": "index.js",
 6 |   "scripts": {
 7 |     "start": "node --experimental-modules --no-warnings node-parent-thread-rxjs.js",
 8 |     "test": "echo \"Error: no test specified\" && exit 1"
 9 |   },
10 |   "author": "Brian De Sousa",
11 |   "license": "ISC",
12 |   "dependencies": {
13 |     "rxjs": "^6.3.3"
14 |   }
15 | }
16 | 


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