Proposal: Support draft function return value with modified draft

[unadlib]

Regarding return values, Mutative has the same behavior as Immer.

An draft function returned a new value and modified its draft. Either return a new value or modify the draft.

For example,

  expect(() => {
    const state = create({ a: 1 }, (draft) => {
      draft.a = 2;
      return {
        ...draft,
      };
    });
  }).toThrowError();

However, there is an irrational aspect to this approach. As long as a modified draft can be finalized, it should be allowed to return any value.

Therefore, we are considering allowing Mutative to support draft functions returning any value.