run another process on nodejs process exit

To run another process on Node.js process exit, you can make use of the child_process module. Here are the steps to achieve this:

1. First, you need to import the child_process module using the require function:

const { spawn } = require('child_process');

1. Next, you can define a function that will be executed when the Node.js process exits. This can be done using the process.on event listener with the "exit" event:

process.on('exit', () => {
  // Code to execute on process exit
});

1. Inside the process.on event listener, you can spawn a new child process using the spawn function. This function takes the command to execute as the first argument and an array of arguments as the second argument:

process.on('exit', () => {
  const child = spawn('node', ['script.js']);
});

In this example, the child process will execute the script.js file using the node command.

1. Optionally, you can handle the output of the child process by listening to its stdout and stderr streams. For example, you can log the output to the console:

process.on('exit', () => {
  const child = spawn('node', ['script.js']);

  child.stdout.on('data', (data) => {
    console.log(`Child process stdout: ${data}`);
  });

  child.stderr.on('data', (data) => {
    console.error(`Child process stderr: ${data}`);
  });
});

1. Finally, you can handle any errors that may occur during the execution of the child process by listening to the error event:

process.on('exit', () => {
  const child = spawn('node', ['script.js']);

  child.stdout.on('data', (data) => {
    console.log(`Child process stdout: ${data}`);
  });

  child.stderr.on('data', (data) => {
    console.error(`Child process stderr: ${data}`);
  });

  child.on('error', (error) => {
    console.error(`Child process error: ${error.message}`);
  });
});

That's it! Now, when the Node.js process exits, the defined function will be executed, spawning a new child process to run the specified command.