Returns whether an addon has been loaded.
loaded, finished = IsAddOnLoaded(index or "name")
- number - The index of the addon in the user's addon list. You cannot query Blizzard-provided AddOns using this parameter.
- string - The name of the addon to be queried. You can query Blizzard-provided addon using this parameter.
- boolean - 1 if the addon has been, or is being loaded, nil otherwise.
- boolean - 1 if the addon has finished loading (the ADDON_LOADED has already been fired for this addon), nil otherwise.