timers in javascript/node.js

timers.js

/**
 * timers in action
 * http://nodejs.org/api/timers.html
 */

// lastly this one is called, because it isn't resolved on the queue until ~50ms
// long after all the other functions are queued up in the event loop
setTimeout(function() {
  console.log(5);
}, 50);

// `setImmediate` functions are queued up "...after I/O events callbacks and
// before setTimeout and setInterval..." but oddly, this doesn't seem to be the
// case. see `setTimeout(fn, 10)`
setImmediate(function() {
  console.log(4);
});

// `setTimeout` with 10ms isn't much more than 0ms, but it is triggered before
// `setImmediate`... not sure why
setTimeout(function() {
  console.log(3.5);
}, 10);

// after the `nextTick` callback is executed, the call stack is empty again, so
// the async tasks start to pushed on to the call stack, 0 being the first to
// run
setTimeout(function() {
  console.log(3);
}, 0);

// since the call stack is empty, and the `setTimeouts` && `setImmediate` and
// queued up, `nextTick` runs at the start of the next event loop cycle
process.nextTick(function() {
  console.log(2);
});

// first function on the call stack - runs first
console.log(1);