Asuka documentation

Asuka makes native apps in Go, for iOS, Android, macOS, Windows, Linux and the web. An app's interface is Go functions that return views; Asuka shows them with each platform's own widgets, and updates only the views that read a signal when it changes.

func Counter() ui.Node {
	count := signal.New(0)
	label := signal.Func(func() string {
		return fmt.Sprintf("Count: %d", count.Get())
	})
	return ui.SafeArea(ui.Style{Align: ui.AlignCenter, Justify: ui.JustifyCenter},
		ui.Text(label),
		ui.Button(ui.ButtonProps{
			Title:   ui.Val("Add"),
			Variant: ui.ButtonFilled,
			OnPress: func() { count.Set(count.Peek() + 1) },
		}),
	)
}

func main() { app.Run(Counter) }

How it works

Your app is Go: its components, its state and the rest of its code. Asuka's core runs the components, lays the views out (flexbox and grid, in Go), and sends what changed to the platform's host, in a batch for each frame. The host makes and updates the platform's own views:

A text field is a UITextField, an EditText, an NSTextField, an EDIT control, a GtkEntry or an <input>; a stack of screens is a UINavigationController, Material's app bar with its back gesture, the Mac window's toolbar with its back button, or libadwaita's navigation view. So an app that sets no style looks as the platform's apps do, and gets their accessibility, text input and scrolling as they have them. The desktop hosts call the system's libraries from Go, without cgo, so a Windows or Linux app builds with Go alone, from any system.

Signals hold the state. A component runs once; when a signal changes, only the props that read it are sent again, without diffing a tree.

The same app runs everywhere. On a phone it fills the screen; on a desktop it's a window the user resizes, and it can open more windows (ui.Window, which a phone hasn't) and have a menu bar with keyboard shortcuts (ui.MenuBar, ignored on a phone). A package for something a platform doesn't have (sensors or home screen widgets on a Mac) answers there that it isn't available, so the app can check and do without.

Asuka needs Go 1.26 or later. Apps run on iOS 16, Android 13 (API 33), macOS 11, Windows 10 and Linux with GTK 4.14 and libadwaita 1.5, and later; and in current browsers. asuka dev runs your app while you work and reloads it as you save: on the simulator, an emulator or a phone, with your Go code on your computer; on the computer itself; or in your browser.

Guides

Reference