Hammerspoon config to send escape on short ctrl press

init.lua

ctrl_table = {
    sends_escape = true,
    last_mods = {}
}

control_key_timer = hs.timer.delayed.new(0.15, function()
    ctrl_table["send_escape"] = false
    -- log.i("timer fired")
    -- control_key_timer:stop()
end
)

last_mods = {}

control_handler = function(evt)
  local new_mods = evt:getFlags()
  if last_mods["ctrl"] == new_mods["ctrl"] then
      return false
  end
  if not last_mods["ctrl"] then
    -- log.i("control pressed")
    last_mods = new_mods
    ctrl_table["send_escape"] = true
    -- log.i("starting timer")
    control_key_timer:start()
  else
    -- log.i("contrtol released")
    -- log.i(ctrl_table["send_escape"])
    if ctrl_table["send_escape"] then
      -- log.i("send escape key...")
      hs.eventtap.keyStroke({}, "ESCAPE")
    end
    last_mods = new_mods
    control_key_timer:stop()
  end
  return false
end

control_tap = hs.eventtap.new({12}, control_handler)

control_tap:start()

This is a great and very helpful gist. I used it to get my application to more reliably trigger the ESCAPE key. Since sending it with the hs.eventtap.sendKey does not seem to reliably do so (especially in applications like Alfred, 1Password, and such.

But the tip by @wezzynl in their comment above got me thinking and it actually does work much faster and more reliable.