hopefully I get this right 2.0

-- must create a anonymous frame so we can track events
local myFrame = CreateFrame("Frame")
myFrame:SetScript(
    "OnEvent",
    function(self, event, ...)
        if event =="PLAYER_LOGIN" then -- fires on login or reload
            -- set all your bars
            MainMenuBarArtFrameBackground:Hide()
            MainMenuBarArtFrame.LeftEndCap:Hide()
            MainMenuBarArtFrame.RightEndCap:Hide()
            ActionBarUpButton:Hide()
            ActionBarDownButton:Hide()
            StatusTrackingBarManager:Hide()
            MainMenuBarArtFrame.PageNumber:Hide()
            -- hide tooltip
            GameTooltip:SetScript("OnShow", GameTooltip.Hide)
            -- set your local r
            local r = {"MultiBarBottomLeft", "Action"}
            -- first loop left action bar buttons
            for b = 1, #r do
                for i = 1, 12 do
                    -- hide your current button
                     _G[r [b] .. "Button" .. i .. "Name"]:SetAlpha(0)
                end
            end
            -- second loop left action bar buttons
            for i = 1, 12 do
                 _G["MultiBarBottomLeftButton" .. i .. "HotKey"]:SetAlpha(0)
            end
            -- third loop action buttons
            for i = 1, 12 do
                -- hide current action button
                _G["ActionButton" .. i .. "HotKey"]:SetAlpha(0)
            end

        elseif event == "PLAYER_ENTERING_WORLD" then -- fires whenever a loading screen is seen
            -- check to see if you are in a pvp map
            if C_PvP.IsPVPMap() or C_PvP.IsRatedMap() or C_PvP.IsBattleground() or C_PvP.IsRatedBattleground() or C_PvP.IsArena() or C_PvP.IsInBrawl() or IsWargame() then
                --show nameplates
                SetCVar("nameplateShowSelf", 1)
                SetCVar("nameplateShowEnemies", 1)
                SetCVar("UnitNameFriendlyPlayerName", 1)
            else
                --toggle nameplates
                SetCVar("nameplateShowSelf", 0)
                SetCVar("nameplateShowEnemies", 0)
                SetCVar("UnitNameFriendlyPlayerName", 0)
            end
        elseif event == "PLAYER_ENTERING_BATTLEGROUND" then
                --show nameplates
                SetCVar("nameplateShowSelf", 1)
                SetCVar("nameplateShowEnemies", 1)
                SetCVar("UnitNameFriendlyPlayerName", 1)
        end
    end
)
-- register events to track
myFrame:RegisterEvent("PLAYER_LOGIN") -- fires on login or reload
myFrame:RegisterEvent("PLAYER_ENTERING_WORLD") -- fires whenever a loading screen is seen
myFrame:RegisterEvent("PLAYER_ENTERING_BATTLEGROUND") -- fires whenever a player enters a battleground