Event loop yaiku mekanisme sing memungkinake Node.js single-threaded kanggo nindakake non-blocking I/O. Terus-terusan ngolah antrian callback: nalika JavaScript mu ilalakua ing siji thread, operasi I/O dikasilake, lan callback-e dilakua dening loop nalika rampung.
Fase-fase loop
Saben iterasi ("tick") pindhah lumaui fase-fase sing urut, saben-sabene duwe antrian callback dhewe:
┌───────────────────────────┐
┌─>│ timers (setTimeout) │ ← expired timer callbacks
│ ├───────────────────────────┤
│ │ pending I/O callbacks │
│ ├───────────────────────────┤
│ │ poll (I/O events) │ ← retrieve new I/O; execute their callbacks
│ ├───────────────────────────┤
│ │ check (setImmediate) │
│ ├───────────────────────────┤
└──│ close callbacks │
└───────────────────────────┘
