# Any links to discussions around Object.deepFreeze? **URL:** \ **Category:** I have questions\ **Created:** [February 20, 2021, 3:55pm UTC](https://es.discourse.group/t/any-links-to-discussions-around-object-deepfreeze/652 "2021-02-20T15:55:19Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![aclaymore](https://yyz2.discourse-cdn.com/free1/user_avatar/es.discourse.group/aclaymore/32/501_2.png) [@aclaymore](https://es.discourse.group/u/aclaymore)\ **Post date:** [February 20, 2021, 3:55pm UTC](https://es.discourse.group/t/any-links-to-discussions-around-object-deepfreeze/652/1 "2021-02-20T15:55:19Z")
In the tc39 notes from 2021/01/25 there was discussion around the mutability of JSON modules. It was mentioned that projects could opt-in to immutability with: > you can simply be the first importer and then you can freeze the object [source](https://github.com/tc39/notes/blob/34be73a9a3aef9a87f74ef4db11ce8bf63625c09/meetings/2021-01/jan-25.md#:~:text=then%20you%20can%20freeze%20the%20object) Deeply freezing an object is non trivial (though easier when source object is known to have come from JSON), so is commonly done by importing a library. **Question:** Does anyone have any links to previous discussions about adding `Object.deepFreeze` Foreseen issues that have probably already come up: - Would it handle cycles? - Tracking cycles will consume more memory but avoids infinite loops - Would it freeze prototypes? - Should it visit just own properties? - Should it freeze `Array.prototype` when obj contains an array? - Would it be configurable? - It could take an argument similar to `JSON.stringify', an array of props to visit - Preference for using `Record` for deep immutability EDIT: rephrased post as a question instead of an idea ---
**Author:** ![ljharb](https://yyz2.discourse-cdn.com/free1/user_avatar/es.discourse.group/ljharb/32/8_2.png) [@ljharb](https://es.discourse.group/u/ljharb)\ **Post date:** [February 20, 2021, 4:09pm UTC](https://es.discourse.group/t/any-links-to-discussions-around-object-deepfreeze/652/2 "2021-02-20T16:09:14Z")
Handling cycles seems like an obvious thing to do, but I don't think there's any reasonable choice to be made about freezing prototypes. If it _does_, then it could have unintended side effects far beyond the user's intention; if it _doesn't_, then it's not actually deeply freezing the object. ---
**Author:** ![theScottyJam](https://yyz2.discourse-cdn.com/free1/user_avatar/es.discourse.group/thescottyjam/32/616_2.png) [@theScottyJam](https://es.discourse.group/u/theScottyJam)\ **Post date:** [February 20, 2021, 11:02pm UTC](https://es.discourse.group/t/any-links-to-discussions-around-object-deepfreeze/652/3 "2021-02-20T23:02:37Z")
Is there much of a use case for deep freezing besides parsing JSON (either with JSON.parse, or with JSON modules)? I could see cases where it might be convenient to deep freeze a nested object literal, but that gets dangerous if you ever want to add some mutable instance of a class to that nested structure. And tuples/records would remove this use case. As an aside: The following code is a little slow, but would allow one to copy a data-only object and deep freeze it. ```javascript JSON.parse(JSON.stringify(data), (_, value) => Object.freeze(value)) ``` ---
**Author:** ![theScottyJam](https://yyz2.discourse-cdn.com/free1/user_avatar/es.discourse.group/thescottyjam/32/616_2.png) [@theScottyJam](https://es.discourse.group/u/theScottyJam)\ **Post date:** [February 21, 2021, 12:23am UTC](https://es.discourse.group/t/any-links-to-discussions-around-object-deepfreeze/652/4 "2021-02-21T00:23:57Z")
I guess there are scenarios when you may be receiving a nested data structure from a library that you would like to freeze (i.e. maybe a request body while in node). If we do implement a deepFreeze function, it could pave a standard way to implement other deep operations, such as deep cloning, or deep equality checking. ---
**Author:** ![lygstate](https://yyz2.discourse-cdn.com/free1/user_avatar/es.discourse.group/lygstate/32/628_2.png) [@lygstate](https://es.discourse.group/u/lygstate)\ **Post date:** [February 22, 2021, 5:10am UTC](https://es.discourse.group/t/any-links-to-discussions-around-object-deepfreeze/652/5 "2021-02-22T05:10:30Z")
How about using [GitHub - tc39/proposal-record-tuple: ECMAScript proposal for the Record and Tuple value types. | Stage 2: it will change!](https://github.com/tc39/proposal-record-tuple)? We can convert a object to records-tuple. ---
**Author:** ![lygstate](https://yyz2.discourse-cdn.com/free1/user_avatar/es.discourse.group/lygstate/32/628_2.png) [@lygstate](https://es.discourse.group/u/lygstate)\ **Post date:** [February 22, 2021, 5:14am UTC](https://es.discourse.group/t/any-links-to-discussions-around-object-deepfreeze/652/6 "2021-02-22T05:14:08Z")
We can add Object.prototype.toImmutable function, so that we can gain > **[tc39/proposal-record-tuple](https://github.com/tc39/proposal-record-tuple)** > > ECMAScript proposal for the Record and Tuple value types. | Stage 2: it will change! For Array, it's turn out to be `tuple`, For Object, it's turn out to be `record` ---
**Author:** ![aclaymore](https://yyz2.discourse-cdn.com/free1/user_avatar/es.discourse.group/aclaymore/32/501_2.png) [@aclaymore](https://es.discourse.group/u/aclaymore)\ **Post date:** [February 26, 2021, 12:23pm UTC](https://es.discourse.group/t/any-links-to-discussions-around-object-deepfreeze/652/7 "2021-02-26T12:23:48Z")
FYI rephrased post as a question, not a proposal. ---
**Author:** ![markm](https://yyz2.discourse-cdn.com/free1/user_avatar/es.discourse.group/markm/32/19_2.png) [@markm](https://es.discourse.group/u/markm)\ **Post date:** [March 16, 2026, 3:21am UTC](https://es.discourse.group/t/any-links-to-discussions-around-object-deepfreeze/652/8 "2026-03-16T03:21:07Z")
See discussion of `harden` at [https://es.discourse.group/t/object-deepfreeze/](https://es.discourse.group/t/object-deepfreeze/)