Why is the component not rendering?

Question

Vue.js

You need to make a custom grid on vue. I ran into a problem when implementing sorting (the mechanism was brazenly borrowed from the off site Grid-component ).
In order not to overload with details, I reproduced the problem in jsfiddle (sorting does not work).
It breaks when the template displays a "local copy" of the input data (currentCellVal property). It is necessary to change the data in the cell, for a single-connected data flow. And most importantly, please explain why this happens and how to fix it?

Answer 1

Don't copy the prop to data, because data is only initialized the first time and will not be updated from the prop.
https://jsfiddle.net/sdzcovuq/