How to activate the button when selecting an element in the table?

Question

JavaScript

How to activate the button when selecting an element in the table and if not selected, then the button is not available? It seems there is an event, but it is impossible to hang up. Help me please.
Example:
https://codepen.io/Vkondr/pen/vYYbgoz

Answer 1

There is already a property containing the selected elements - great, using it, you can make a calculated property that controls the activity of the button:
<v-btn :disabled="disabled"

computed: {
  disabled() {
    return !this.selected.length;
  },
},