---
id: faq
title: Frequently Asked Questions
sidebar_label: FAQ
---

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## Q: How does Immer work?

Read the (second part of the) [introduction blog](https://medium.com/@mweststrate/introducing-immer-immutability-the-easy-way-9d73d8f71cb3).

## Q: Does Immer use structural sharing? So that my selectors can be memoized and such?

A: Yes

## Q: Does Immer support deep updates?

A: Yes

## Q: I can't rely on Proxies being present on my target environments. Can I use Immer?

A: Yes [details](https://immerjs.github.io/immer/docs/installation#immer-on-older-javascript-environments)

## Q: Can I typecheck my data structures when using Immer?

A: Yes

## Q: Can I store `Date` objects, functions etc in my state tree when using Immer?

A: Yes

## Q: Can I use Maps and Sets?

A: Yes

## Q: Is it fast?

A: Yes

## Q: Idea! Can Immer freeze the state for me?

A: Yes