How to determine if nodejs child_process failed due to timeout?

Question

If I do child_process.exec('mycommand', { timeout: 5000 }, callback), I don't know if the resulting error is caused by a timeout or some other reason. Is there a way to determine whether the failure was caused by the { timeout: 5000 } option passed to child_process?

Answer 1

There's only one way which may not be quite reliable.
So be careful when you use it for your needs

How it works:

1. When the timeout is triggered, the parent process sends out a default SIGTERM signal unless you override in the options {killSignal : 'SIGINT'}
2. Once the child process is exited, the parent process's call back cb(err,stdout,stderr) is called by populating err.code to null and err.signal to SIGTERM or whatever it is

So you can check for err.signal in the callback. And again this is not quite reliable as you can kill the child process from task manager or using shell's kill command.