How to get the parameter from the array obtained from the selected checkboxes?

Question

Vue.js

An array is created consisting of the data of the selected checkboxes, the data of one element includes: "title", "cost", "id".
you need to get cost from the resulting array, in order to further calculate the total cost of all selected elements,
please tell me how to get cost and throw it into a new array, consisting only of cost values.

the source code is here, but I don’t know how to run vue in this editor
https://jsfiddle.net/h6cdn9ys/1/

this is how the result looks like

Answer 1

computed: {
  summary() {
    return (this.choosenSize?.cost ?? 0) + this.choosenTopping.reduce((acc, n) => acc + n.cost, 0);
  },
},