How to call component methods (Ionic 4 + Vue.js 2)

For example, if I use the ion-tabs and want to change the current tab manually, there is a select method provided for this component which returns a promise. But I don’t understand how to use given methods of components (in Vue.js).

Does anyone know how this works? The corresponding doc is here:

I don’t understand how to use the given methods of components at all. There are several examples, mostly for Angular, which are outdated. I seek a solution for Vue.js only.

Do you have the answer already?
I have also the same question.