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 Deeply freezing an object is non trivial (though easier …

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.

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 s…

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 d…

How about using GitHub - tc39/proposal-record-tuple: ECMAScript proposal for the Record and Tuple value types. | Stage 2: it will change! ? We can convert a object to records-tuple.

We can add Object.prototype.toImmutable function, so that we can gain [image] 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 r…

FYI rephrased post as a question, not a proposal.

Any links to discussions around Object.deepFreeze?

I have questions

markm March 16, 2026, 3:21am 8

See discussion of harden at https://es.discourse.group/t/object-deepfreeze/

Topic		Replies	Views
Object.freezeRecord 💡 Ideas	3	91	April 19, 2026
Object.deepFreeze 💡 Ideas	52	523	April 16, 2026
Propagate frozen state on object spread 💡 Ideas	8	665	August 31, 2021
Frozen array / object syntax 💡 Ideas proposal	2	312	July 28, 2022
Proposal Records (a new one) 💡 Ideas	16	232	April 29, 2026

Any links to discussions around Object.deepFreeze?

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