Write functions that limit how often a callback can execute ?

[sudoUgando]

Write functions that limit how often a callback can execute (useful for search inputs, scroll events).

[EimanTahir071]

Write functions that limit how often a callback can execute (useful for search inputs, scroll events).

Throttle (max once every X ms)
Executes immediately, then at most once per interval.

js
export function throttle(fn, wait = 200, options = {}) {
let lastCallTime = 0;
let timeoutId = null;

const { leading = true, trailing = true } = options;

function invoke() {
lastCallTime = Date.now();
timeoutId = null;
fn.apply(this, arguments);
}

return function throttled(...args) {
const now = Date.now();
const remaining = wait - (now - lastCallTime);

const context = this;

if (remaining <= 0 || remaining > wait) {
  if (timeoutId) {
    clearTimeout(timeoutId);
    timeoutId = null;
  }
  if (leading) invoke.apply(context, args);
  else {
    lastCallTime = now;
    if (trailing) {
      timeoutId = setTimeout(() => {
        lastCallTime = Date.now();
        fn.apply(context, args);
      }, wait);
    }
  }
  return;
}

if (trailing && !timeoutId) {
  timeoutId = setTimeout(() => {
    timeoutId = null;
    if (!leading) lastCallTime = Date.now();
    fn.apply(context, args);
  }, remaining);
}

};
}
Use when: you want frequent updates but capped (e.g., scrolling, resize).