all components with onSelectionChange have a bad api design

[thisisamir98]

Problem Description

The Selection type in Nextui with TypeScript has a few issues that impact its usability and correctness.

Issues Identified

1. Cannot Retrieve Length
   The Selection type, which can be either 'all' or a Set, lacks a consistent way to retrieve its length.
   This makes it challenging to perform operations that require knowledge of the number of elements in the selection.

2. Limited Iteration Support
   The Selection type currently only offers methods like toString or valueOf in TypeScript.
   This limitation prevents convenient iteration over the selection, hindering common use cases.

3. Error in Official Docs Example
   The example provided in the official documentation leads to a TypeScript error:

Type 'string' is not assignable to type 'SetStateAction<Set<string>>'.ts(2345)

Nextui Version: 2.2.9
TypeScript Version: 5.3.3

[thisisamir98]

closing as the author of nextui pointed out that the Selection API comes from react-aria.
adobe/react-spectrum#5606