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useState in react under the hood

M Hassan khan answered on March 16, 2023 Popularity 8/10 Helpfulness 5/10

answer useState in react under the hood

useState in react under the hood

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useState() is a JavaScript function defined in the React library.
When we call this function, it returns an array with two values:

    current state - the current value of this state
    state setter - a function that we can use to update the value of this
	state

Because React returns these two values in an array, 
we can assign them to local
variables, naming them whatever we like. For example:

const [toggle, setToggle] = useState();
// I can also provide whole hook e.g
const toggleHook = useState(true);   // naming does not matter
// if you console log toggleHook is equal to true and you also have
// setter function available. 

Look at the example below for better understanding. 

=====================================================================
  
  *****Example*******
  
  
  useState function returns two values in an array. to understand that
  we take this example.
  
  function twoValues() {
  return [0, 1];
}

let [first, second] = twoValues();

I can also do like this 

let fourth = twoValues();

// fourth will be equal to [0,1] if you console log it.

If I do const [fifth, sixth] = fourth;

// on conosle log fifth = 0 and sixth = 1

If I dont care about the the first returned value 
I can also write like this 

const [_, fifth] = fourth // fifth will be equal to 1  _ means I dont care
// about what value is it. dont want to define it.

with the same concept , we can apply to useState destructuring. 


Happy Coding !!!

Popularity 8/10 Helpfulness 5/10 Language javascript

Source: Grepper

Tags: destructuring javascript use-state

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Contributed on Mar 16 2023

M Hassan khan

0 Answers Avg Quality 2/10

useState in react under the hood

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