What is throttling in JavaScript?

Again a jargonish word, but let me demystify it for you.

let me help you

It's nothing but a simple technique we use to prevent unnecessary function calls to improve app's performance.

Unlike Debouncing, here we block a function call for a particular time if it's been executed recently. Or we could also say that throttling ensures a function call regularly at a fixed rate.

Let's look at the below example,

<!DOCTYPE html>
<html lang="en">
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <button class="btn">Click here</button>
        <script src="index.js"></script>
let count = 0;
function submitData(query){
   // some api call


first example

In the above example, if you click 10 times in 2000ms, Function will be called 10 times, as you can clearly see in the above example.

It's a very expensive operation, and as dev, our job is to make operations as cheap as possible.

Let's see how throttling helps us to make these operations cheaper.

function throttle(fn,delay){
  let last = 0;
here ...args is optional I've used this in case, if you 
want to pass some parameters you can use ...args
  return (...args)=>{
    const now = new Date().getTime();
    if(now - last < delay){
   last = now;
   return fn(...args)


const magicFunction = throttle(submitData,1000);

let count = 0;
function submitData(){
   // some api call



Now, if you click 10 times in 2000ms, Function will be called 2 times only, as you can see in the code. We have blocked the function call for 1000ms.

That's how we can implement the throttling technique to improve our app's performance

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