nodejs child_process spawn and exec doesn't kill process on process.kill(pid)

Question

I am working in nodejs. I'm trying to run .cmd file using child_process spawn and exec. But none seems to work. Spawn successfully run the .cmd file when I run this script spawn('cmd', ['/c', 'start start_wMBusServices_CLI.cmd']).

but on killing the process using process.kill(pid) it generates following error.

spawn.kill() doesn't kill process at all.

I did some digging and I found that the process (pid = 16580) is missing in task manager.

And child_process.exec just create pid and doesn't run .cmd at all.

Now, what I want is, to kill the process when I click that stop button.

I need a simple script to kill this process.

Here's my whole code

let exec = null;
let pId = null;

function startStop() {
  try {
    if (!pId) {
      exec = spawn('cmd', ['/c', "start start_wMBusServices_CLI.cmd"])
      
      // <-- execFile didn't work -->
      -------------------------------

      // exec = execFile(executablePath, { encoding: 'utf-8' }, function (err, stdOut, stdErr) {
      //   console.error(err);
      //   console.error(stdErr);
      // })
      pId = exec.pid
      console.log(pId);
      // if(exec.killed)
      //   pId = null

    }
    else if (pId) {
      // didn't work
      --------------
      // exec.kill()

      // generates error shown before
      -------------------------------
      process.kill(pId)
    }
  } catch (err) {
    console.error(err);
  }
  console.log(process);
}