Returns the data passed to a custom app page.
Wix passes data to custom app pages that you can use when implementing the page's business logic.
Call the getAppPageData() function to retrieve the data and use it in your code.
The data retrieved by this function is different for each type of custom app page.
For more information, see App Page Data.
Learn more about building custom app pages.
If you call the getAppPageData() function in the code for a page that isn't
a custom app page, the function returns null.