Attempt to set/get item from localstorage

[IanVS]

Fixes #204

In Windows environments, it's possible for browsers to have a localStorage and yet not have access to it. This ends up throwing an Access is denied error when attempting to get or set from localStorage.

This change adds some additional safety checks into hasLocalStorage to set, get, and remove a test item inside the try block.

[rt2zz]

interesting. Can we simplify the check to simply running a localStorage.getItem('test key') call? I would assume that would throw and there is no need to also test set and remove?

[rt2zz]

also does sessionStorage suffer from the same quirk?

[IanVS]

Can we simplify the check to simply running a localStorage.getItem('test key')

That would handle this particular case, yes. But, it does not save us if localStorage is at capacity and cannot be written to, which is where the setItem is useful.

does sessionStorage suffer from the same quirk?

Honestly I don't know. I don't think I've been seeing any sessionStorage errors, so I wouldn't know how to test it. I'd say leave it alone unless it's determined to be a problem.

[IanVS]

This is a pretty good thread with different options for checking localStorage: https://mathiasbynens.be/notes/localstorage-pattern#comment-9

[rt2zz]

👍 I decided to simplify the check to just getItem for now. This module is very sensitive to startup time and I want to be conservative with anything that could impact this.