Local state exists within a component.

However many times this component re-renders, the data will be preserved.

Use local state in a function component with useState.

Update state with   useState(newValue) .

const updateCartValue = useState({ cartValue: 0 })

const cartState = useState(0)
const cartValue = cartState[0]
const updateCartValue = cartState[1]

const [cartValue, updateCartValue] = useState(0)

const [cartValue, updateCartValue] = useState(1)

useEffect  and  useState  have to be imported from the package "react-hooks."

useEffect  and  useState  are the only two hooks that exist.

Hooks didn’t exist when React was first created.

A hook is a function that allows us to hook into React functionalities.