How to call a function in a other thread

Question

I have on my code a heavy algorithm in a function in node.js.

I want to called this function on a other thread to save performances. I have tried :

let ChildProcess = require('child_process');
const thread1 = ChildProcess.spawn(function ()
{
  reloadData();
});

function reloadData() { /* code */ }

But it don't working. I want to called this function on the current .js file, not in a other .js file Thank you !

Take a look at answer [here](https://stackoverflow.com/questions/18613023/how-to-create-threads-in-nodejs) and also [node doc](https://nodejs.org/api/child_process.html). — Pierre-Luc Perron, Dec 03 '17 at 18:26
The problem is that i have not found any example to create a thread which call directly a function in the current .js file, i see only examples to create a thread which call a seperated .js file — XWarzor, Dec 03 '17 at 18:36

jfriend00 · Accepted Answer · 2023-08-17T18:43:09.730

You can't find the example you're looking for because that's not how any of the child_process functions work. You can't do what you're trying to do.

You need to put your other functions in a NEW node.js program and then you use the child_process module to run that other program.

You can then use various different forms to communicate between the two processes such as stdio or tcp networking.

You also aren't using the arguments to spawn() correctly. If you look at the first argument in the doc, that first argument is a command or another program to run in your local system. It's not some piece of local Javascript.

Note: This answer was originally written in 2017. Nodejs now has WorkerThreads which you can read about how to use here.

Thanks, i have understand my problem, i mark this question resolved — XWarzor, Dec 03 '17 at 19:02

score 0 · Answer 2 · answered Aug 17 '23 at 18:22

With worker_threads!

const {
  Worker,
  isMainThread,
  setEnvironmentData,
  getEnvironmentData,
} = require('node:worker_threads');

if (isMainThread) {
  setEnvironmentData('Hello', 'World!');
  const worker = new Worker(__filename);
} else {
  console.log(getEnvironmentData('Hello'));  // Prints 'World!'.
}

The above code uses a single file. Instead of __filename you can use any other js file.

How to call a function in a other thread

2 Answers2