onChanged.addListener also exists on Storage Areas

[lachlanmcdonald]

The documentation states that onChanged exists on the storage object:

chrome.storage.onChanged.addListener(
  callback: function,
)

However, in @types/chrome, the onChanged event exists on each individual Storage Area:

declare namespace chrome.storage {
    export interface StorageArea {
        // ...
        onChanged: StorageAreaChangedEvent;
    }
}

• Determine where onChanged is present.
• Update the class as necessary.

[lachlanmcdonald]

It appears that the onChanged event can apply to a singular storage area (e.g. chrome.storage.local.onChanged), or across all available storage areas (i.e. chrome.storage.onChanged)