How do I make the keybinding be detected but not intercepted?

[NightMachinery]

I have a keybinding on b. This causes the b key to not do its original function.

I have tried doing

hs.eventtap.keyStroke({}, 'b')

in the keybinding function, but this causes a useless infinite loop.

[jparoz]

If you're using the hs.hotkey API to make a key binding, it will override any existing behaviour for that key combination. If you just want to monitor key events, consider using hs.eventtap.new instead. This API allows you to choose whether to post the event or not, by returning either true or false from your callback. You can't directly create an event tap for a single key, but you can use something like the following to approximate the behaviour:

bEventTap = hs.eventtap.new({hs.eventtap.event.types.keyDown}, function(event)
    if event:getCharacters() ~= 'b' then return end
    -- do stuff here
    return false  -- don't delete the event
end)
bEventTap:start()

[muescha]

the other way around is to save the handler of the binding and disable and enable it between the keystroke:

(pseudocode)

hotkeyHandler = hs.hotkey.bind(modifier, key, message, function()
if something then
   -- do things
 else
   -- do original keystroke
   hotkeyHandler:disable()
   hs.eventtap.keyStroke(modifier, key)
   hotkeyHandler:enable()
 end

to avoid the infinite loop you need to disable the hotkeyHandler

PS:
I have created some helper with this behaviour:

bindHotkey

when it should fire only in specific apps or in a specific app and tab (additional functionality: I disabled the logging - otherwise it always shows a log entry if it the handler is disabled/enabled)

Source:

• https://github.com/muescha/dot_hammerspoon/blob/master/Helpers/SendKeysOnlyInApp.lua#L123

Usages:

• https://github.com/muescha/dot_hammerspoon/blob/master/Functions/ChromeTabToNewWindow.lua#L9
• https://github.com/muescha/dot_hammerspoon/blob/master/Functions/ChromeNewWindow.lua#L10
• https://github.com/muescha/dot_hammerspoon/blob/master/Functions/MailMateDisableCmdW.lua#L13

HotkeyBindSafe

which I need to disable my keyhandler with the hyper key so that I can resend a keystroke with fewer modifiers (my hyper is cmd/opt/ctrl/shift but i need to send only cmd+key):

Source:

• https://github.com/muescha/dot_hammerspoon/blob/master/Helpers/HotkeyBindSafe.lua#L27
  Usages:
• https://github.com/muescha/dot_hammerspoon/blob/master/Functions/KeyMapping.lua#L7