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What are exit codes in Node.js and what do they indicate?

Exit codes are numeric values returned by a Node.js process when it terminates. They tell the OS (or parent process) whether the process exited successfully or due to an error.

  • 0 — success, normal exit.

  • Non-zero — some kind of error or abnormal termination.

// Preferred: set exit code and let process exit naturally
process.exitCode = 1;

// Forceful exit (use sparingly)
if (criticalError) {
  process.exit(1);
}

// Check exit code in shell after running
// $ node app.js
// $ echo $?  // prints the exit code

Setting process.exitCode allows the event loop to finish pending operations before exiting with the specified code. process.exit(1) forces immediate termination. The shell command echo $? shows the exit code of the last executed process, which is useful for CI/CD pipelines and scripts.

Know the difference between process.exit() and process.exitCode. The preference for exitCode over exit() shows you understand graceful shutdown practices.

What are exit codes in Node.js and what do they indicate? | Hiprup