When does the view cache clear?

[ronen-e]

Hi Everyone.

I was working with mobx-state-tree and I created a view for a simple fullName property combining firstName and lastName

seeing as how mobx-state-tree caches the results, I was wondering how can I be 100% certain the results would be computed again when needed (e.g when firstName changes).

I was hoping someone here knows or can point me in the right direction.

[jamonholmgren]

@ronen-e Any properties that are accessed within a view are then "remembered" as being accessed, which then ensures that the computation gets computed again when they change.

I don't have the code handy for showing you how this is done, but it seems to be pretty reliable to me.

[ronen-e]

@jamonholmgren I checked the source code (both mobx-state-tree and mobx) and it is reliable.
I noticed that when using getters they are wrapped with mobx.makeObservable and that when using functions they are assigned to the view model.

My specific case was using an impure function such as

getDate() {
  return self.name + ': ' + Date.now()
}

in this case the Date.now() makes it only useable as a view function in React components like this:

<span>{store.getDate()}</span>

Not as a getter:

get date() {
  return self.name + ': ' + Date.now()
}

<span>{store.date}</span>