pause child process from node.js

Question

If I have a child process running from node.js

const k = cp.spawn('bash');

k.stdin.end(`do long process`);

k.stdout.pipe(process.stdout);
k.stderr.pipe(process.stderr);

I learned recently that using ctrl+z that I can stop/pause a process completely and then restart it by typing fg.

I think the same thing can be accomplished by using these signals:

`kill -STOP ${k.pid}`
`kill -CONT ${k.pid}`

how can I send these signals to the child process, to stop/restart the child process?

Answer 1

Alright I jumped the gun a bit here, this solves it just fine, using k.kill('SIGSTOP') and k.kill('SIGCONT'):

#!/usr/bin/env node

const cp = require('child_process');

const k = cp.spawn('bash');

k.stdin.end(`
   var=0;
   while true; do 
       var=$((var+1))
       echo "count: $var"
       sleep 0.01
   done;
`);

k.stdout.pipe(process.stdout);
k.stderr.pipe(process.stderr);


const pauseAndRestart = () => {

    setTimeout(() => {
        k.kill('SIGSTOP');
        setTimeout(() => {
            k.kill('SIGCONT');
            pauseAndRestart();
        },2000);
    }, 2000);

};

pauseAndRestart();

this script will pause and restart the child process over and over. (Tested on MacOS only). I am not sure about the ramifications of pausing a process and how it might differ with Windows or Linux. Any insight there appreciated.