Cat will display the content of the cat object. In the old Vue, to get this result we had to write {{ cat | json }}.
A thing to be wary of is loops in our objects. If our object contains a circular reference, and you wrap it in mustaches, this will not work. These objects are more common than you would think. HTML elements, for example, are JavaScript objects that contain references to a parent node; the parent node in turn contains a reference to its children. Any such tree structure would cause the mustaches to print an infinite description of the object. When you actually do it, Vue simply throws an error and refuses to work. The error you would see in the console is actually thrown by the internal method used to print ...
