> Deprecated: > Product subscription app extensions won't be supported as of December 3, 2025. You should migrate existing product subscription app extensions to [purchase options extensions](/docs/apps/build/purchase-options/purchase-options-extensions). You can use the Layout utility to adjust your content based on the user's screen size. Layout returns `'compact'` on mobile devices and at narrow screen widths, and `'regular'` otherwise.
Layout
| |
| setOnChange | (onChange: (layout: Layout) => void) => void
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### Layout
| Name | Type | Description |
| --- | --- | --- |
| horizontal | "regular" | "compact"
| |