A snippet to create app specific keybindings

[madmaxieee]

Idea

• When app_bind is called, register a keybinding normally
• Use hs.application.watcher to watch current active app
• activate/deactivate these keybindings based on current active app
• useful for remapping a keybinding in an app that doesn't natively support that

Example Usage:

local app_bind = require("app_bind").app_bind

app_bind("Zen", { "cmd" }, "d", function(app)
    -- pin or unpin a tab, this is currently not customizable in Zen
    hs.eventtap.keyStroke({ "alt" }, "p", 0, app)
end)

-- hide an app on cmd + w instead closing the window, good for apps that takes a lot of time to create new windows
local function hide_on_cmd_w(app_name)
    local app_bind = require("app_bind").app_bind
    app_bind(app_name, { "cmd" }, "w", function(app)
        local num_windows = #app:allWindows()
        if num_windows == 1 then
            app:hide()
        else
            app:focusedWindow():close()
        end
    end)
    app_bind(app_name, { "cmd", "shift" }, "w", function(app)
        app:focusedWindow():close()
    end)
end

Implementation

local M = {}

local app_bind_handlers = {}

---@param app_name string
---@param modifiers string[]
---@param key string
---@param fn fun(app: hs.application)
function M.app_bind(app_name, modifiers, key, fn)
    local handler = hs.hotkey.bind(modifiers, key, function()
        local app = hs.application.find(app_name, true)
        if app then
            fn(app)
        end
    end)
    if app_bind_handlers[app_name] == nil then
        app_bind_handlers[app_name] = {}
    end
    table.insert(app_bind_handlers[app_name], handler)
end

---@diagnostic disable-next-line: unused-local
App_watcher = hs.application.watcher.new(function(app_name, event_type, app)
    if event_type == hs.application.watcher.activated then
        for name, handlers in pairs(app_bind_handlers) do
            if name == app_name then
                for _, handler in ipairs(handlers) do
                    handler:enable()
                end
            else
                for _, handler in ipairs(handlers) do
                    handler:disable()
                end
            end
        end
    elseif event_type == hs.application.watcher.deactivated then
        if app_bind_handlers[app_name] == nil then
            return
        end
        for _, handler in ipairs(app_bind_handlers[app_name]) do
            handler:disable()
        end
    end
end)
App_watcher:start()

return M