How do I know which keys have been updated?

[lmk123]

I wanted to save the states, and then I saw How to persist states in the documentation, but I have a special case: my states can be huge, and I only want to save the really updated part.

For example:

const state = proxy(
  readStorage() || {
    count: 0,
    text: 'hello',
  },
)

subscribe(state, (changes) => {
  // I hope changes will be `{ count: 123 }`, not the whole state `{ count: 123, text: 'hello' }`
  setStorage(changes)
})

state.count = 123

[dai-shi]

Valtio core doesn't track props, so you have to do it on your end.
subscribeKey is provided from valtio/utils, but it works only for a single key.

subscribeKeys is also proposed #887, but nobody has worked on since then.

---

We have unstable_ops, but it's considered for library authors or advanced users.

valtio/src/vanilla.ts

Line 276 in 0870cd1

callback: (unstable_ops: Op[]) => void,