Keep NodeMCU connected to WiFi

wifi-watch.lua

-- If you have a recent firmware from the dev branch you could do away with that ugly timer
-- by relying on WiFi events and (re-)acting accordingly. See wifi.sta.eventMonReg() at 
-- https://github.com/nodemcu/nodemcu-firmware/wiki/nodemcu_api_en#wifistaeventmonreg

-- init all globals
...

wifiReady = 0

function configureWiFi()
    wifi.setmode(wifi.STATION)
    wifi.sta.config(WIFI_SSID, WIFI_PASS)
    wifi.sta.connect()
    tmr.alarm(WIFI_ALARM_ID, 1000, 1, wifi_watch)
end
-- while NOT connected to WiFi you blink a LED, see below
function wifi_watch()
    -- 0: STATION_IDLE,
    -- 1: STATION_CONNECTING,
    -- 2: STATION_WRONG_PASSWORD,
    -- 3: STATION_NO_AP_FOUND,
    -- 4: STATION_CONNECT_FAIL,
    -- 5: STATION_GOT_IP.
    status = wifi.sta.status()
    if status == 5 then
        -- only do something if the status actually changed
        -- you could of course combine these two 'if's but it's more explicit for this gist
        if wifiReady == 0 then
            wifiReady = 1
            print("WiFi: connected")
            turnWiFiLedOn()
            -- do something
        end
    else
        wifiReady = 0
        print("WiFi: (re-)connecting")
        turnWiFiLedOnOff()
        wifi.sta.connect()
    end
end
function turnWiFiLedOnOff()
    turnWiFiLedOn()
    tmr.alarm(WIFI_LED_BLINK_ALARM_ID, 500, 0, function()
        turnWiFiLedOff()
    end)
end
function turnWiFiLedOn()
    gpio.write(WIFI_LED, gpio.HIGH)
end
function turnWiFiLedOff()
    gpio.write(WIFI_LED, gpio.LOW)
end

When I run the code I get:

> configureWiFi()
stdin:6: tmr 10 does not exist
stack traceback:
    [C]: in function 'alarm'
    stdin:6: in function 'configureWiFi'
    stdin:1: in main chunk

I set:

WIFI_ALARM_ID = 10
WIFI_LED_BLINK_ALARM_ID = 11
WIFI_LED = 0

My fault wrong timer id. Thanks for your help.