Sometimes it's hard to know who's keeping your process alive

why-wont-you-die.js

var timeouts = [];
var intervals = [];
var sockets = [];
var setTimeout_    = setTimeout;
var clearTimeout_  = clearTimeout;
var setInterval_   = setInterval;
var clearInterval_ = clearInterval;

var Socket = require('net').Socket;
var emit = Socket.prototype.emit;
Socket.prototype.emit = function (event) {
  if (event === 'connect') {
    sockets.push(this);
  }
  else if (event === 'close') {
    var self = this;
    sockets = sockets.filter(function (socket) { return socket !== self });
  }
  return emit.apply(this, arguments);
}

function forgetTimeout (timeout) {
  timeouts = timeouts.filter(function (wrapper) {
    return wrapper.timeout !== timeout;
  });
}

function getStack (type, time) {
  var stack = new Error().stack.split('\n').slice(3).map(function (s) { return s.replace(/^\s+/, ''); }).join('\n')
  return time + 'ms ' + type + ' created ' + stack;
}

global.setTimeout = function (fn, time) {
  var timeout = setTimeout_.apply(this, arguments);
  timeouts.push({ timeout: timeout, stack: getStack('timeout', time) });
  setTimeout_(forgetTimeout, time, timeout);
  return timeout;
}

global.clearTimeout = function (timeout) {
  forgetTimeout(timeout);
  return clearTimeout_.apply(this, arguments);
}

global.setInterval = function (fn, time) {
  var interval = setInterval_.apply(this, arguments);
  intervals.push({ interval: interval, stack: getStack('interval', time) });
  return interval;
};

global.clearInterval = function (interval) {
  intervals = intervals.filter(function (wrapper) {
    return wrapper.interval !== interval;
  });
  return clearInterval_.apply(this, arguments);
}

module.exports = function report () {
  return {
    intervals: intervals.map(function (i) { return i.stack.split('\n') }),
    timeouts: timeouts.map(function (i) { return i.stack.split('\n') }),
    sockets: sockets.map(function (s) { return {local: s.localPort, remote: s.remotePort} })
  }
}