A script that will disable bluetooth when the lid of a Macbook is closed.

hammerspoon-bluetooth-lid-close-handling.lue

require "string"

-- Make sure to install Hammerspoon (brew install --cask hammerspoon) and blueutil (brew install blueutil).
-- Ensure to give sufficient access in macOS so that the commands can be ran:
-- -- System Settings -> Privacy & Security -> Accessibility -> Allow Hammerspoon
-- -- System Settings -> Privacy & Security -> Bluetooth -> Select app "Hammerspoon"
-- Place this file in your home folder, then open Hammerspoon and click "Reload config"

function checkBluetoothResult(rc, stdout, stderr)
    -- Use for debugging
    --print(string.format("Command executed with rc=%d", rc))
    --print(string.format("stdout: '%s'", stdout or "nil"))
    --print(string.format("stderr: '%s'", stderr or "nil"))
    if rc ~= 0 then
        print(string.format("Error executing `blueutil`: rc=%d stderr=%s stdout=%s", rc, stderr, stdout))
    end
end

function bluetooth(power)
    print("Setting Bluetooth to " .. power)
    -- Convert power to 0/1 instead of on/off
    local powerState = power == "on" and "1" or "0"
    local t = hs.task.new("/opt/homebrew/bin/blueutil", checkBluetoothResult, {"--power", powerState})
    t:start()
end

function f(event)
    if event == hs.caffeinate.watcher.systemWillSleep then
        bluetooth("off")
    elseif event == hs.caffeinate.watcher.screensDidWake then
        bluetooth("on")
    end
end

watcher = hs.caffeinate.watcher.new(f)
watcher:start()