Why are useState variables `const` in react?

Question

My understanding is, when using useState(), we should declare the array as such:

const [someBooleanValue, setSomeBooleanValue] = useState(false)

Instead of

let [someBooleanValue, setSomeBooleanValue] = useState(false)

Normally, const is used on variables that won't be changing. Here, someBooleanValue will be changing. What is going on that allows us to use the const keyword in this case?

Answer 1

In React Hooks with a Functional Component, your code gets a single value of state for each call into your functional component. React handles the storage separately and returns that current value via useState on each execution of your code, providing the latest state value.

From the docs:

We declare a state variable called count, and set it to 0. React will remember its current value between re-renders, and provide the most recent one to our function. If we want to update the current count, we can call setCount.

So in this case, we use const because the value should never be reassigned in our code.