Vue.js update subtotal in array

Question

After some research i find this post what have an example about how to manage a complex array in Vue.js https://forum.vuejs.org/t/vuex-best-practices-for-complex-objects/10143/2

I have create this jsbin ( https://jsbin.com/jocezud/5/edit?html,js,output ) to make some test but i´m stuck at this point. I want to make some totals based in the checked topics:

A) When the checkbox of each Topic is checked the price value must be copied to the subTotal value.

B) Also every user must have the userTotal updated with the sum of the subTotal of the checked Topics .

Here is a capture about my goal.

Thanks in advance

Answer 1

Finally i get it working with also a Final total and a Reset feature.

Here is the actual working version ( https://jsbin.com/jocezud/12/edit?html,js,output )

Anyway i think there must be a better way to, in this case run some calculations of data in arrays when a array value change happens, right?