Timer Functions in JavaScript
From the Async JavaScript cheat sheet · Timers & Event Loop · verified Jul 2026
Timer Functions
Schedule code execution after delays or at regular intervals using built-in timer functions
javascript
// setTimeout
const timeoutId = setTimeout(() => {
console.log('Executed after 2 seconds');
}, 2000);
// setInterval
const intervalId = setInterval(() => {
console.log('Every second');
}, 1000);
// Clear timers
clearTimeout(timeoutId);
clearInterval(intervalId);
// setImmediate (Node.js)
setImmediate(() => {
console.log('Execute after I/O');
});💡 setTimeout executes once after a delay, setInterval repeats
⚠️ Timers are not guaranteed to execute at exact times
🔄 Always clear intervals and timeouts when no longer needed
⚡ Use setTimeout with 0ms to defer execution to next tick