Question: mutation of an object that is not a part of the draft

[prodderman]

Hello!

Is there a way to avoid mutation of the object that is not a part of the draft? (except deepCopy)

const defaultPart = {
    y: 1,
};

const state = {
  x: undefined
};

const newState = create(state, draftState => {
  stateDraft.x ??= defaultPart;
  stateDraft.x.y = 2; // mutates original object
})

console.log(defaultPart.y) // 2

I tried to create draft inside but it doesn't finalize

...
const newState = create(state, draftState => {
  stateDraft.x ??= create(defaultPart)[0];
  stateDraft.x.y = 2;
})

console.log(newState.x) // Proxy(Object) { ... }

[unadlib]

hi @prodderman , Mutative does not support finalizing drafts across multiple scopes draft.

Perhaps you can use it like this,

const defaultPart = {
  y: 1,
};

const state = {
  x: undefined,
};

const newState = create(state, (draftState) => {
  const [subDraft, finalize] = create(defaultPart);
  subDraft.y = 2;
  const state = finalize();
  draftState.x ??= state;
});

console.log(newState.x); // { y: 2 }
console.log(defaultPart.y); // 1

[unadlib]

You can also use it like this.

const defaultPart = {
  y: 1,
};

const state = {
  x: undefined,
};

let [stateDraft, finalize] = create(state);
stateDraft.x ??= defaultPart;
[stateDraft, finalize] = create(finalize());
stateDraft.x.y = 2;
const newState = finalize();

console.log(newState.x); // { y: 2 }
console.log(defaultPart.y); // 1

You must ensure that the correspondence between the immutable tree and the draft is maintained.