optimize state handlers

[kqiq]

hi im one of your old students that was attend in your class as guest in 2020 webdev that was a great experience for me .
i do some changes to this file for the following reasons :) :
The useMemo hook is not needed since initialValue is not a function that depends on props.
The spread operator ...props is removed since it is not used in the code.
The if (payload !== undefined) check is not needed since ...payload in the spread operator will automatically ignore undefined values.

[kqiq]

The constructor method is removed and the storage property is initialized directly.
The isAvailable method is converted to an instance method by removing the static keyword.
The getFile and saveFile, getFileWriter methods are converted to async functions and the Promise constructors are replaced with await expressions.

[kqiq]

The Boolean constructor is removed since the result of the logical OR operator || is already a boolean.