Get a unfrozen object from "snapshot"

[saivanji]

snapshot function returns a frozen object with writable: false in it's descriptor.

Is it possible to get an object which will be writable from the snapshot function?

[dai-shi]

You have to copy the snapshot object, for example using _.cloneDeep.

If you feel it's not optimal (I do so actually), there might be a better way. Why not using proxy state instead?
Or, deep cloning is unavoidable for certain use cases, like we do in proxyWithHistory.

valtio/src/vanilla/utils/proxyWithHistory.ts

Line 10 in 7fe26c2

const deepClone = <T>(obj: T): T => {

[saivanji]

@dai-shi yeah, deep cloning is undesirable (we use it inside the onChange handler, which will hurt typing experience).

Can you please clarify, what you mean by "using proxy state instead"?

[dai-shi]

"proxy state" means an object returned by proxy(). So, it simply means "can you avoid relying on snapshots?"

Because snapshot is a frozen snapshot by nature, you can't modify.

const originalObj = { count: 0 };
const snapshotObj = Object.freeze({ ...originalObj });
++originalObj.count; // shouldn't change the snapshot object
// If you need to modify the snapshot object, you need to copy:
const newModifiableObj = { ...snapshotObj };
++newModifiableObj.count; // now it's possible to modify