Lua script for hammerspoon for easy switching between apps.

hammerspoon-init.lua

— Define your hyper key
local hyper = {"ctrl", "alt", "cmd", "shift"}

— Define a table of applications with their bundle identifiers and hotkeys
local apps = {
    {key = "C", bundleID = "com.todesktop.230313mzl4w4u92"}, — Cursor App
    {key = "B", bundleID = "com.google.Chrome"},             — Google Chrome
    {key = "P", bundleID = "com.postmanlabs.mac"},           — Postman
    {key = "I", bundleID = "com.jetbrains.intellij"},        — IntelliJ
    {key = "T", bundleID = "com.googlecode.iterm2"},         — iTerm
    {key = "S", bundleID = "com.tinyspeck.slackmacgap"},     — Slack
    {key = "M", bundleID = "com.microsoft.teams2"},          — Microsoft Teams
    {key = "O", bundleID = "com.microsoft.Outlook"}          — Outlook
}

— Command to find the bundle ID of an app
— osascript -e 'id of app "YourAppName"'

— Table to store the previously focused window for each app
local previousWindows = {}

— Table to store the last focused window within the app for cycling
local lastFocusedWindows = {}

— Function to switch to the next window of the specified app
local function switchAppWindow(bundleID)
    — Get the application object
    local app = hs.application.get(bundleID)

    — If the app is not running, launch it
    if not app then
        hs.application.launchOrFocusByBundleID(bundleID)
        return
    end

    — Get all windows of the app
    local windows = app:allWindows()

    — If no windows are found, launch the app
    if #windows == 0 then
        hs.application.launchOrFocusByBundleID(bundleID)
        return
    end

    — Sort windows to ensure consistent order
    table.sort(windows, function(a, b) return a:id() < b:id() end)

    — Get the currently focused window
    local currentWindow = hs.window.focusedWindow()

    — Check if the current window belongs to the app
    local isCurrentWindowInApp = false
    for _, window in ipairs(windows) do
        if window == currentWindow then
            isCurrentWindowInApp = true
            break
        end
    end

    — Handle single window toggle
    if #windows == 1 then
        if isCurrentWindowInApp then
            — Toggle back to the previous window
            if previousWindows[bundleID] and previousWindows[bundleID]:isVisible() then
                previousWindows[bundleID]:focus()
                previousWindows[bundleID] = nil
            else
                previousWindows[bundleID] = currentWindow
                windows[1]:focus()
            end
        else
            — Focus on the app's window and store the current window
            previousWindows[bundleID] = currentWindow
            windows[1]:focus()
        end
        return
    end

    — Handle multiple windows cycling
    if not isCurrentWindowInApp then
        — Focus on the last focused window within the app or the first window
        if lastFocusedWindows[bundleID] and lastFocusedWindows[bundleID]:isVisible() then
            lastFocusedWindows[bundleID]:focus()
        else
            windows[1]:focus()
        end
        previousWindows[bundleID] = currentWindow
        return
    end

    — Find the index of the last focused window within the app
    local lastFocusedIndex = 1
    if lastFocusedWindows[bundleID] then
        for i, window in ipairs(windows) do
            if window == lastFocusedWindows[bundleID] then
                lastFocusedIndex = i
                break
            end
        end
    end

    — Move to the next window in the list
    local nextIndex = lastFocusedIndex % #windows + 1
    windows[nextIndex]:focus()

    — Update the last focused window
    lastFocusedWindows[bundleID] = windows[nextIndex]
end

— Bind the function to the hyper key + specified key for each app
for _, app in ipairs(apps) do
    hs.hotkey.bind(hyper, app.key, function() switchAppWindow(app.bundleID) end)
end