JavaScript Debounce vs Throttle: When Should You Use Each?

JavaScript Debounce vs Throttle: When Should You Use Each?

Both exist to solve the same underlying problem — a browser event that fires far more often than your code actually needs to react to it. A user typing into a search box fires an input event on every keystroke. A user scrolling or dragging fires dozens of events a second. Running an API call, a layout recalculation, or a re-render on every single one of those is wasteful at best and janky at worst. Debounce and throttle both slow that flood down — the real question isn't "which one is more efficient," it's what shape of behavior you actually want : debounce says "wait until things go quiet, then do it once." Throttle says "keep doing it, but never more often than this." Once that distinction clicks, most "which one do I reach for" questions answer themselves. The 5 demos below are all real, running JavaScript — type, scroll, move your mouse — so you can watch each technique's actual firing pattern instead of reading about it secondhand…