Abnormal Exit

[Alan Gutierrez]

I'm writing command line utilities in Node.js. Here's a snippet that is
a source of some concern for me.

try {
options = require('arguable')(__filename);
} catch (error) {
console.error('error: ' + e.message);
console.error(e.usage);
process.exit(1);
}

frobinate(options.severity);

Essentially, I'm calling an options parser and finding errors that
prevent me form continuing. I want to exit with a non-zero exit code.

However, if I exit abruptly, I find that the console is not always
flushed. Sometimes on Windows. Sometimes when piping stderr.

I'm wondering when I can count on a flush of stderr before exit, when I
can't, and what you feel is the right way to exit from a command line
program, if you have any thoughts on the matter.

Currently, I'm creating a main function, surrounding that in a try/catch
block, and throwing special exceptions to indicate that the error does
not involve a stack trace.

--
Alan Gutierrez - http://github.com/bigeasy - http://twitter.com/bigeasy

[Dominic Tarr]

you can throw anything in js, even an empty string.
(a good way to break a test framework)

would this work?

stderr.on('drain', function () {
process.exit(1)
})

console.error('fail')

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[Alan Gutierrez]

Wouldn't that abruptly exit the program the first time stderr drains? I
imagine that it drains multiple times during the life of the program, if
I write warnings while running.

Currently, I'm doing...

try {
main();
} catch (e) {
if (e.code != null && !isNaN(e.code))
process.on('exit', function () { process.exit(e.code) });
else
throw e;
}

But, I'm trying to imagine situations where catching that error in that
way will cause the program to keep on going, instead of petering out.

[Dominic Tarr]

oh, you would have to assign the 'drain' listener after you've decided to exit.