Beginner LevelNode JS
How do timers work in Node.js (setTimeout, setInterval, unref, ref)?
❓ Interview Prompt: Explain setTimeout, setInterval, clearTimeout, clearInterval, and unref()/ref() preventing process exit.
Timers in Node.js mirror browser APIs but include server-specific control methods:
•
'timer.unref()': Allows the Node.js event loop to exit even if the timer is still active!
•
'timer.ref()': Re-activates a previously unref'd timer to keep the process alive.
Code Implementation Example
javascript
const timer = setInterval(() => {
console.log('Background heartbeat check...');
}, 5000);
// Prevent this interval timer from keeping the Node.js process alive on exit!
timer.unref();💡Using timer.unref() to allow Node.js process exit despite active timers.
🎯 Interview Key Takeaway
Call timer.unref() on background timers to allow the Node.js process to exit cleanly when main work finishes.
#Timers#setTimeout#unref#Beginner
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