Apple - How can I display the SSID I am connected to in the Menu extensions area?

The best solution I use for adding the SSID to the menu bar is turning off Apple's menu item and using WiFi Signal app from Adrian Granados:

• https://www.adriangranados.com/?q=apps/wifi-signal
• https://itunes.apple.com/us/app/wifi-signal/id525912054?mt=12

It's much fuller featured than just displaying the SSID, but it does that job nicely. I am a very satisfied customer of all his Mac apps as they are powerful, well engineered and updated regularly.

1. Download Debookee Tools from the Mac App Store and launch it.

2. Click it on the menu bar for its dropdown and uncheck Channel and Debookee Icon, and check Launch at Login.

3. Change the location by command-dragging each menu bar item where you want them.

SSD is now always displayed in the menu bar!

You can do this with Hammerspoon (see http://hammerspoon.org) and a bit of lua. Add the following to Hammerspoon's config file. Don't forget to save and do 'reload config' from the Hammerspoon menu bar icon:

wifiMenu = hs.menubar.newWithPriority(2147483645)
wifiMenu:setTitle(hs.wifi.currentNetwork())

wifiWatcher = nil

function ssidChanged()
    local wifiName = hs.wifi.currentNetwork()
    if wifiName then
        wifiMenu:setTitle(wifiName)
    else 
        wifiMenu:setTitle("Wifi OFF")
    end
end

wifiWatcher = hs.wifi.watcher.new(ssidChanged):start()

Haven't tested it on Sierra, but works nicely on 10.11.6.