Why always let props = $props() instead of const ?

[Fd929c2CE5fA]

https://svelte.dev/docs/svelte/$props

I noticed that all the examples use let instead of const, is there a reason or something to be aware of here?
Are there any side effects if const is used, and if so, should they be cautioned or warned about?

[brunnerh]

If you use const, you cannot reassign the variable, that is about it.

So in scenarios where you destructure and have at least one property you want to change, you have to use let. E.g.

<script>
  let { value = $bindable(), ...rest } = $props();
</script>
<input bind:value {...rest} />

[Fd929c2CE5fA]

Yes, $bindable is a situation that need reassign, but in most other cases, it does not seem to reassign?
In other words, if I don't intend to reassign the variable, then there will be no harm to use the const, right?

[brunnerh]

Correct.

(Aside from potentially a small loss of performance due to the additional scoping/assignment rules, though if you are worried about that, you should be using var instead. This probably pales in comparison to all the rendering and updating work caused by a component.)