Worker Threads Promise

Worker Threads implementation with promises to support request-response communication between master and child thread.

If you are using Node version 12- be sure to use the argument --experimental-workers.

Promise implementation adds very low latency that can be considered as unimportant.

Install

``bash
npm i worker-threads-promise
`

Usage


./main.js
`js
const Worker = require('worker-threads-promise');
const path = require('path');

const worker = new Worker(path.join(__dirname, './worker.js'));

(async () => {
const res = await worker.postMessageAsync(1000);
console.log(res);

})();
`

./worker.js
`js
const {parentPort} = require('worker_threads');
const Worker = require('worker-threads-promise');
Worker.connect(parentPort);

parentPort.on('message', data => { //you can use await too
return new Promise(resolve => {
setTimeout(() => {
resolve(data);
}, data);
});
});
`




Options

$3

It will throw timeout exceed error after given amount of milliseconds.

Default: No Timeout

./main.js
`js
const Worker = require('worker-threads-promise');
const path = require('path');

const worker = new Worker(path.join(__dirname, './worker.js'));

(async () => {
const res = await worker.postMessageAsync(5000, {
timeout: 1000
}).catch(e => {
console.log(e);
});
})();
`

./worker.js
`js
const {parentPort} = require('worker_threads');
const Worker = require('worker-threads-promise');
Worker.connect(parentPort);

parentPort.on('message', data => {
return new Promise(resolve => {
setTimeout(() => {
resolve(data);
}, data);
});
});
`

$3

It will prevent event loop to remain active when waiting for response.

Default: false

./main.js
`js
const Worker = require('worker-threads-promise');
const path = require('path');

const worker = new Worker(path.join(__dirname, './worker.js'));

(async () => {
const res = await worker.postMessageAsync(5000, {
timeout: 1000,
unref: true
}).catch(e => {
console.log(e);
});
})();
`

./worker.js
`js
const {parentPort} = require('worker_threads');
const Worker = require('worker-threads-promise');
Worker.connect(parentPort);

parentPort.on('message', data => {
return new Promise(resolve => {
setTimeout(() => {
resolve(data);
}, data);
});
});
`

$3

You can also use transfer list for async calls, you may use 3rd parameter for them.

`js
await worker.postMessageAsync(5000, null, []);
`

As worker-threads-promise extends native Worker, you can use all other features of Worker classes using instance of worker-threads-promise`.