Computed properties execute without being accessed

Hi @ctrlplusb, apologies for reporting this again but I’m still seeing some issues with computed properties executing by default in v4.0.1. I spent a bit of time and I was able to track it down. It basically happens when you have more than one model with action on one model and computed prop on another. When the action is executed and changes model’s local state the computed prop on another model also executes. Here is a simple test to illustrate this:

test('computed properties should not execute when not accessed', () => {
  let computedCount = 0;

  const store = createStore({
    user: {
      firstName: 'Mary',
      lastName: 'Poppins',
      fullName: computed(
        [(state) => state.firstName, (state) => state.lastName],
        (firstName, lastName) => {
          computedCount += 1;
          return `${firstName} ${lastName}`;
        },
      ),
      setFirstName: action((state, payload) => {
        state.firstName = payload;
      }),
    },
    group: {
      data: {},
      change: action((state) => {
        state.data.somedata = 1;
      }),
    }
  });

  store.getActions().group.change();

  // assert which currently fails
  expect(computedCount).toBe(0);
});

I noticed that when I turn this line off:

https://github.com/ctrlplusb/easy-peasy/blob/71ad696f3780a1d67cc8c865e56db3d661d0cb9d/src/extract-data-from-model.js#L172

I see a correct behavior but of course my understanding of the code is pretty limited.

[ctrlplusb]

Will be in next release. 👍

[ctrlplusb]

Thanks for the feedback @mkuklis - very helpful to hear your own real world experience.

I reviewed our source code (around 30 models) and I haven’t seen a single case where computed prop is used inside the action. I did find one case where computed prop was used inside another computed prop (probably not a right thing to do anyway).

This should be ok still 🙏