Send previous state as the 3rd argument to store subscriptions

What problem is this solving

I think the subscription feature is awesome, however it can be more versatile if it were targeted or at least revel what has changed. At least certain logic can behave differently or just sort of react to particular piece of the state.

This has always been a pain with Vuex subscriptions.

Proposed solution

onStoreStateChange (mutation, state, prevState) {
}

more like watches.

or at least allow us to do

store.$subscribe (onStoreStateChange, 'countables.inner.count')

which targets an inner prop of a state

Describe alternatives you’ve considered

usage of watch on the state data

[posva]

Note events is dev only and comes from Vue

[fvlasenko]

You could not send events key together to the events path callback Otherwise, you have to write an extra field in the repository in order to understand what caused the change state: () => ({ size: { path: 'size', width: 1800, height: 2500, depth: 600, cover: { path: 'size.cover', //i want to remove this field state: false, value: 100, }, events.key -> ‘state’, events.path -> ‘size.cover’ I would like to see the full path to the parameter inside the object so that I can work with this path later