App Store links

Link a website to its iOS app the way Apple's marketing guidelines allow, written in the project's own framework, styling and component conventions. $ARGUMENTS, when given, names the app or gives its App Store URL or ID; otherwise use the app configured in the project.

Words used below:

• App ID: the app's numeric App Store ID (App Store Connect calls it the Apple ID), the digits after id in its product URL.
• Product URL: the app's App Store page, https://apps.apple.com/<country>/app/<slug>/id<APP ID>.
• Badge: Apple's "Download on the App Store" artwork, linked to the product URL.
• Clear space: the empty margin around the badge, at least one quarter of its height.
• Smart App Banner: Safari's native banner, switched on by the apple-itunes-app meta tag. Safari draws, shows and dismisses it.
• Credit line: Apple's trademark attribution in the site's legal information.

Sources

Apple's pages are the source of truth. Re-read the rules on the first two before writing code; where they differ from this file, follow Apple and tell the user.