Binding to multiple button clicks

A solution for n keypresses

Very late to the party but there's little to no info on this, so I thought I should really put this here considering this is one of the only search results for this.

My solution is a bit more elegant then some others (in my opinion); there are definitely some things that could be improved about it but I'm not really familiar enough with Lua or Hammerspoon to fix them.

It should work to assign a shortcut to as many consecutive keypresses as you want.

Read the code comments for an explanation of how it works. I've tried to be as detailed as possible, in an effort to make it more beginner friendly for those that don't know much about coding and those that aren't that familiar with Lua or Hammerspoon (like me).

require("hs.timer") -- Load timer module, used for timing

keyDownCount = 0 -- Keypress counter, used later in the program to store the number of times the key has been pressed
keyMultipressGapTime = 0.3 -- Max time between consecutive keypresses, used to determine when the user has stopped pressing the key
keyMaxPressCount = 3 -- Max number of key presses
testKeyCode = 18 -- Key code to bind shortcut to (in this case the 1 key)

-- READ CheckKeyDownCount FUNCTION CODE (BELOW) FIRST
-- Function to press a key with code
-- This isn't completely intuitive so I'm including it
-- Im sure there's a better way of doing this but this is what I figured out
function PressKey(keyCode) 
    keyDown = hs.eventtap.event.newKeyEvent(keyCode, true) -- Create new keydown event using the keycode passed in the keycode argument
    keyDown:setProperty(hs.eventtap.event.properties.eventSourceUserData, 1) -- Sets user data byte of keydown event to 1, used later to prevent keydown event handler from self triggering
    keyDown:post() -- Fire keydown event
    hs.eventtap.event.newKeyEvent(keyCode, false):post() -- Create and fire keyup event using the keycode passed in the keycode argument
end

-- READ EVENT HANDLER CODE (BELOW) FIRST
-- Function to check the number of times the key was pressed and act accordingly
-- Pretty self explanatory
function CheckKeyDownCount()
    CheckKeyDownCountTimer:stop() -- Stops keydown timer so it doesn't repeat
    -- There may be a better way of doing this but I can't find a way to creating and restarting a non repeating timer without creating a whole new timer object every time

    if keyDownCount == 1 then -- Perform action based on number of keypresses
        hs.alert("Pressed once")
        PressKey(testKeyCode)
    elseif keyDownCount == 2 then
        hs.alert("Pressed twice")
    elseif keyDownCount == 3 then
        hs.alert("Pressed thrice")
    end
    
    keyDownCount = 0 -- Reset keypress counter
end

CheckKeyDownCountTimer = hs.timer.new(keyMultipressGapTime, CheckKeyDownCount) -- Creates timer for determining when the user has stopped pressing the key
-- Time interval is set to the max time between consecutive keypresses
-- Runs the CheckKeyDownCount function at end of time interval
-- IMPORTANT: Time interval automatically resets when timer is stopped and started

-- Creates keydown event handler
-- FOR BEGINNERS: An event handler is a routine that runs when triggered by an event (kind of like an interrupt if you know what that is), normally they call a function, like below
-- FOR BEGINNERS CONTINUED: The timer above is also an event handler of sorts, with the event being the end of the time interval, event handlers are very useful because they allow asynchronous code execution
-- FOR BEGINNERS CONTINUED: In this case asynchronous code execution means that the program will continue executing until an event needs to be handled, the program will then stop where it is, handel the event, and then jump back to where it left off
multipressBtnShortcuts = hs.eventtap.new({hs.eventtap.event.types.keyDown}, function(event) 
    -- FOR BEGINNERS: "function(event)" creates anonymous function containing the below code and passes it the keydown event as an object called "event" (Just makes the code neater, you could use a separate function if you want)
    -- FOR BEGINNERS CONTINUED: An anonymous function is just a function without an identifier (name), instead they're objects and often behave kinda like variables (look this up, it's kinda hard to explain and not relevant here)
    -- RANDOM NOTE: Also turns out all functions in lua are anonymous which is pretty interesting, the interpreter just converts the structure "function foo(x) return 2*x end" into "foo = function (x) return 2*x end" 
    
    if event:getKeyCode() == testKeyCode and event:getProperty(hs.eventtap.event.properties.eventSourceUserData) == 0 then -- Check if keycode is the shortcut keycode and check if the user data byte is set to 0 (default)
        -- The user data byte check is to prevent the event handler from triggering itself (SEE PressKey FUNCTION ABOVE)
        -- I'm sure there's a better way to do this but I cant find it

        event:setType(hs.eventtap.event.types.nullEvent)  -- Null the keypress event
        -- Overrides the keypress, remove if you don't want the original keypresses to be overridden
        -- I'm sure there's a better way to do this but I cant find it
        
        keyDownCount = keyDownCount + 1 -- Add one to keypress counter

        if CheckKeyDownCountTimer:running() then -- If the max key press gap timer is running stop it (NOTE: Stopping and starting it also resets it)
            CheckKeyDownCountTimer:stop() 
        end

        if keyDownCount < keyMaxPressCount then -- If keypress counter is less then the max number of keypresses restart the max key press gap timer (NOTE: Stopping and starting it also resets it)
            CheckKeyDownCountTimer:start() 
        else -- Alternativly, if the keypress counter is greater than or equal to the max number of keypresses run the CheckKeyDownCount function 
            CheckKeyDownCount()
        end            
    end
    return false -- Ends the anonymous function by returning false, not sure if this is really necessary but it's what other people seem to do 
end)

multipressBtnShortcuts:start() -- Starts the keydown event handler