# What is throttling in JavaScript?
Again a jargonish word, but let me demystify it for you.
It's nothing but a simple technique we use to prevent unnecessary function calls to improve app's performance.
Unlike [Debouncing](https://aamchora.hashnode.dev/what-is-debouncing-in-javascript), 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,
```html
Throttling
```
```js
let count = 0;
function submitData(query){
// some api call
console.log("result",count++)
}
document.querySelector(".btn").addEventListener("click",()=>{
submitData();
})
```
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.
```js
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){
return;
}
last = now;
return fn(...args)
}
}
const magicFunction = throttle(submitData,1000);
let count = 0;
function submitData(){
// some api call
console.log("result",count++)
}
document.querySelector(".btn").addEventListener("click",magicFunction);
```
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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