Whats the correct way to update a object?

[AndreiTS]

Example:

const state = proxy({ a: { b: 0, c: 1 });

I know I can update the state like this:

state.a.b = 2;
state.a.c = 3;

But what if I have a big object, can I do like this:

state.a = {
    b: 2,
    c: 3,
}

Or should I create a new proxy?

state.a = proxy({
    b: 2,
    c: 3,
})

How is this going to affect react re-renders?

[dai-shi]

state.a = {
    b: 2,
    c: 3,
}

That's just fine. If you want a partial update, this works too.

Object.assign(state.a, {
    b: 2,
    c: 3,
})

[decipher-cs]

Can I assume this also applies to arrays?

const state = proxy({ s: [{ foo: "bar" }] })
state.s = [{ bar: "foo" }] // This will work

[dai-shi]

Or should I create a new proxy?

It's the same thing.

How is this going to affect react re-renders?

It depends on how you use useSnapshot, but it's generally render optimized even if you replace the big object.