[taoxin]

Ah.. you need a binding function to wrap the state-derived content into a reactive UI element, see: https://vanjs.org/tutorial#state-derived-child. I made the change in your code to make it work: https://jsfiddle.net/rkfmpx06/1/

[seanlaff]

Oh! I understand, thanks for walking through that. Yes very terse compared to the equivalent react :)