What are the different phases of the Event Loop?

1) Timers: setTimeout/setInterval callbacks, 2) Pending callbacks: I/O callbacks deferred, 3) Idle/prepare: internal use, 4) Poll: fetch new I/O events, execute I/O callbacks, 5) Check: setImmediate callbacks, 6) Close callbacks: socket.on('close'). Each phase has a FIFO queue.