By default, binding to a path such as app.selected.name.first will 'observe' changes at the leaf level only.
To observe changes higher up the path, such as swapping the app.selected object (selected person), replace the '.' by '^' immediately after the highest-level item to be 'observed'.

For paths in which objects higher in the path may sometimes be null or undefined, add onError=null or onError='' in order to suppress error rendering and default to an empty string.

Example:

<div data-link="selected^name.first onError=null "></div>

<!-- data-linking-->

<input data-link="selected^name.first onError=null " />

<!-- data-bound tag-->

{^{>selected^name.first onError=null }}