Node.js does not detect process.stdout pipe closing

node-yes-simplistic.js

// this terminates: yes | head
// this hangs: node node-yes-simple.js | head
// per mhart, this is entirely expected
while(true) {
  process.stdout.write('{"yes": "yes"}\n');
}

node-yes.js

// Keep saying yes until interrupted or someone closes your output pipe:

var running = true;
function say_yes() {
  if (running) {
    process.stdout.write('{"yes": "yes"}\n');
    process.nextTick(say_yes);
  } else {
    process.exit(0);
  }
}

process.stdout.on('error', function(err) {
  running = false;
  if (err.code === 'EPIPE') {
    // expected if output pipe closed, e.g. by `head`
    process.exit(0);
  } else {
    process.stderr.write(JSON.stringify(err) + '\n');
    process.exit(1);
  }
});

You're starving the event loop with the infinite while.

Try this:

function writeYes() {
  process.stdout.write('{"yes": "yes"}\n');
  process.nextTick(writeYes);
}
writeYes();

(NB: The difference with the example in epipebomb is that the process there actually terminates so the events are processed after the for loop finishes - it's not infinite like the while examples here)

Updated. Thanks!