How to call a function on a component every time an input parameter changes in VUE JS?

Question

JavaScript

Hello. There was such question it is impossible to find the answer to it. There is a code https://jsfiddle.net/zoufgbc8/
there is a buttons component. It is necessary that when changing the values ​​in DATA in the parent, a function was called in this component (child). How to implement this?

Answer 1

in the watch component: { propName: function() { ... this code is executed when the propName value changes}}

Answer 2

In your case, it may not be necessary: ​​https://jsfiddle.net/kulakoff/9u3yzfLs/