In which block should the vm.$watch('abc', function (newVal, oldVal) { construct be inserted in vue-cli?

Question

Vue.js

I decided to try an alternative version of watch https://ru.vuejs.org/v2/api/#vm-watch
but I don’t understand where exactly to insert the construction (replaced vm with this - right?) I
’m constantly confused - the manual is written for this vm (why- then) - but in fact there is no vm in single-file scripts ,
plz tell me
thanks!

Answer 1

vm is short for view-model. It's essentially a vue instance, and inside the component, it's this.
$watch is usually placed in a component's hooks - created() or mounted() for example.