Know the Table Name you want to access – not the Name of the UI Part Metadata Item itself, but of one of its Tables that has Include In Data Set checked.
Call Aptify.framework.utility.cache.getMetaData and use the UI Part Metadata Item in the callback.
So, for the Entity Cards array, which has a JSON UI Part that looks like this:
The "data" parameter passed to the callback function will look like this:
Because getMetaData() is a function that accesses the cache, it's possible for it to return synchronously if the requested metadata is already in the browser's local storage:
However, you as the programmer are not in control of the cache, so the best practice is to stick to using the function asynchronously.