8192.js

#!/usr/bin/env node

const { execSync, spawn, exec } = require('child_process')

// Pass '0', '1' or '2' as only argument.
const type = Math.max(Math.min(process.argv[2] ? parseInt(process.argv[2], 10) : 0, 2), 0)

console.log('Type', type)

// Note: executing 'command' which outputs more than 8192 characters of data.
// This is caused by a process.exit(0) (in the 'command' script) that appears
// immediately after a large write operation, e.g. a console.log() over 8192 bytes.
// If this is the case, the process may exit before the write is complete.
//
// To fix, replace the process.exit(0) with process.exitCode = 0

const cmd = 'insert command here'

if (type === 0) {
  let stdout = execSync(cmd)
  console.log(stdout.buffer)
  console.log('Length', stdout.toString('utf8').length) // 8191
}

if (type === 1) {
  const child = spawn(cmd)
  let out = ''
  child.stdout.on('data', (data) => {
    out += data.toString()
    console.log('Length', out.length) // 8191
  });
  child.stdout.on('end', (data) => {
    console.log('Done')
    console.log('Final length', out.length) // 8191
  });
}

if (type === 2) {
  const child = exec(cmd, (err, stdout, stderr) => {
    console.log(stdout.length) // 8191
  })
}