> 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.

## Props optional = ? | Name | Type | Description | | --- | --- | --- | | initialValue | Layout | | | setOnChange | (onChange: (layout: Layout) => void) => void | | ### Layout | Name | Type | Description | | --- | --- | --- | | horizontal | "regular" | "compact" | |