A function that takes a single parameter:
The function returns an object that contains these properties:
The total width of the item, which includes the item width, left and right padding, left and right border, and left and right margin.
The total height of the item, which includes the item height, top and bottom padding, top and bottom border, and top and bottom margin.
Set to true to create a column break; otherwise, false.
The values returned by the itemInfo function must be set based on the item index and can't reliably depend on item data.
Because the itemInfo function takes an index (and not an ItemPromise), it can'’t wait for an item to be returned from the data source. This is fine for synchronous data sources, such as WinJS.Binding.List, because the item is readily available and can be looked up by index. It’ is difficult, however, to look up data in an asynchronous data source based on the provided index value (itemIndex), because the items might be added out of order and the data for the items might not yet be available, so your itemInfo function can'’t reliably perform a key-based lookup.
Minimum WinJS version