---title: 'proxy'section: 'Basic'description: 'Create a proxy object.'---
# proxy
The proxy tracks changes to the original object and all nested objects, notifying listeners when an object is modified.
```jsimport { proxy, useSnapshot } from 'valtio'
const state = proxy({ count: 0, text: 'hello' })```
#### Mutate from anywhere
You can make changes to it in the same way you would to a normal js-object.
```jssetInterval(() => { ++state.count}, 1000)```
#### Optimizations: Noop and batching
Updates that set the value of a property to the same value are ignored. Subscribers will not be informed of a version change.
```jsconst state = proxy({ count: 0 })
state.count = 0 // has no effect```
Multiple changes in the same event loop tick to will be batched together. Subscribers will be notified of a single version change.
```jsconst state = proxy({ count: 0, text: 'hello' })// subscribers will be notified once after both mutationsstate.count = 1state.text = 'world'```
#### Nested proxies
Proxies can be nested in other proxy objects and updated as a whole.
```jsximport { proxy, useSnapshot } from 'valtio'
const personState = proxy({ name: 'Timo', role: 'admin' })const authState = proxy({ status: 'loggedIn', user: personState })
authState.user.name = 'Nina'```
#### Gotchas
If you reassign the proxy to a entirely new object, it will stop working.
```jsxlet state = proxy({ user: { name: 'Timo' } })
subscribe(state, () => { console.log(state.user.name)})// will not notify subscribersstate = { user: { name: 'Nina' } }
// insteadlet state = proxy({ user: { name: 'Timo' } })
subscribe(state, () => { console.log(state.user.name) // logs "Nina"})// will notify subscribersstate.user.name = 'Nina'```
Not everything can be proxied. Generally, you are safe if it is serializable. Classes can also be proxied. But avoid special objects.
```jsx// these won't work - changes to these objects won't cause updates// to store state that is unproxied see the docs on refconst state = proxy({ chart: d3.select('#chart'), component: React.createElement('div'), map: new Map(), // see proxyMap storage: localStorage,})
// this will workclass User { first = null last = null constructor(first, last) { this.first = first this.last = last } greet() { return `Hi ${this.first}!` } get fullName() { return `${this.first} ${this.last}` }}const state = proxy(new User('Timo', 'Kivinen'))```