AlgorithmsTiming and eventsRuns in your browserReviewed October 1, 2026

Throttle Visualizer

Allow a function to run at most once per time interval, ignoring the extra events. Interactive step-by-step animation with JavaScript code, complexity and front-end use cases.

Localprivate by defaultFastno sign-up path

Timing and eventsTime: O(1) per eventSpace: O(1)

Wait (ms)User events

Events

Cooldown

fn() runs

0ms500ms1000ms1500ms2000ms2500ms3000ms

Now: 0 ms

Step 1 / 10

A throttled function runs at most once every 300 ms. Events that arrive during the cooldown are ignored.

JavaScript

1function throttle(fn, wait) {
2  let last = 0;
3  return (...args) => {
4    const now = Date.now();
5    if (now - last >= wait) {
6      last = now;
7      fn(...args);
8    }
9  };
10}

Tip: use the arrow keys to step and the space bar to play or pause.

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Throttle Visualization and Animation

Allow a function to run at most once per time interval, ignoring the extra events. Remember when the function last ran. On each event, check whether the wait time has passed. If yes run it and update the time; if not ignore the event. Time complexity: O(1) per event. Space complexity: O(1). Scroll, mousemove, drag and resize handlers that must keep the UI responsive while still updating regularly.

How to use Throttle Visualizer

Remember when the function last ran.
On each event, check whether the wait time has passed.
If yes run it and update the time; if not ignore the event.
Press Play, or step through with the arrow buttons and change the input to see how it reacts.

Questions

What is Throttle?

Allow a function to run at most once per time interval, ignoring the extra events.

What is the time complexity of Throttle?

Time: O(1) per event. Space: O(1).

Where do front-end developers use Throttle?

Scroll, mousemove, drag and resize handlers that must keep the UI responsive while still updating regularly.

Does this upload my data?

No. This converter runs in your browser for ordinary use, so the input is not sent to a backend by this tool.

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