Execution of arbitrary JavaScript code (not command) in NodeJS child process

Question

What is the easiest way to run some code (not command!) in a different process and communicate its result with the main process?

So I have a quite intensive task that needs to be split up into different processes. What's the easiest way to do something like this?

// in main process
var otherProcess = createAnotherProcess(function() {
    console.log("this code is ran in another process");
    return "some data";
});
otherProcess.on("done", function(data) {
    console.log(data); // will output "some data"
});

Having a single source code file that is able to run code in multiple processes would be amazing! Is this even possible? I've tried reading a bit about "child_processes" in node but find it a little too convoluted.

Any help?

nodejs.org/api/…

CherryDT
– CherryDT

2022-03-08 00:21:03 +00:00
Commented Mar 8, 2022 at 0:21 — CherryDT
– CherryDT, Commented Mar 8, 2022 at 0:21

chovy · Accepted Answer · 2011-10-19 14:36:04Z

5

var spawn = require("child_process").spawn;
var stat = spawn("dstat", ["-r", "--noheaders", "--nocolor"]);


var output = function (output_data) {
  //do something with output_data
};

stat.stdout.on("data", output);

http://nodejs.org/docs/v0.4.11/api/child_processes.html

answered Oct 19, 2011 at 14:36

chovy

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1 Comment

Luca Matteis Over a year ago

So I cannot keep a single source code file? I need to split it into another .js file and call it using spawn("node myfile.js")?

bjornd · Accepted Answer · 2011-10-19 14:36:26Z

2

To run some command in child process you can use child_process.spawn method.

If you want to run some heavy JS code you can split it execution to chunks to not block the IO using process.nextTick.

answered Oct 19, 2011 at 14:36

bjornd

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1 Comment

Takeshi Tokugawa YD Over a year ago

Thank you for the asnwer. The process.spawn and siminal methods are focused on exectuing of command, not JavaScript code as question author asked. May I ask you to add some example with executing of JavaScript code, not commands?

SuperStormer · Accepted Answer · 2022-03-15 00:15:42Z

1

Use dimas-parallel (on npm):

var dimas = require('dimas-parallel');

dimas.execute(function() {
  // do some stuff on another process
});

edited Mar 15, 2022 at 0:15

SuperStormer

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answered Jul 19, 2015 at 10:45

shudima

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Comments

Birkenstab · Accepted Answer · 2022-03-14 23:36:39Z

0

You can use node -e <code>

Example:

const { spawn } = require('child_process')

const child = spawn('node', ['-e', 'console.log("in other process", process.pid)'])

child.stdout.on('data', data => {
    console.log(data.toString())
})

answered Mar 14, 2022 at 23:36

Birkenstab

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