React hooks are functions JavaScript that you import from React.

The reason we use useState is because we want it when 
We can not change the value of a variable in react directly like JavaScriptWe use useState.
import {useState} from "react";const [state, setState] = usState(0); => initial value varible statesetsetState(5); => change value varible state

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Use to useHistory change pages Suppose we put a button on the home page
We want to go to the about page by pressing that button
To do this we use useHistory.
To use this hook, follow the procedure below:
1- import {useHistory} from ‘react-router-dom’;inside function2- const history = useHistory(); 3- const apply = () => {
history.push('about');
}
4- <button onClick={apply}>Login</button>

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App.js

light dark theme is for when we want the graphical environment of our application or site
It has two black and white theme modes that the user can easily change each one by opening a button And it works with the site or application environment. The choice of black theme is due to less damage to the user's eyes.
To Create a light dark theme you need to write the following code in App.js:
import UseState, ThemeProvider, and SplashPage

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