Immutable const?

Isiah Meadows isiahmeadows at
Tue Nov 8 17:58:27 UTC 2016

JS doesn't have immutable types, which is why `Object.freeze` simply says
"don't change this object's own properties". Frozen objects make for nice
enumerated types, but JS has no notion of immutability. Additionally, you
have to take into account the internal slots, which freezing objects has no
effect on (it only has an effect with the internal `object.[[Get]]` and
`object.[[Set]]` methods).


Isiah Meadows
me at

On Tue, Nov 8, 2016 at 8:57 AM, Reinis Ivanovs <dabas at> wrote:

> This idea sounds like having a version of the `const` keyword that also
> freezes objects, but that's a far cray from what Immutable.js does, which
> is about persistent data and collection methods. Freezing also doesn't work
> on things that use mutator methods like Map or Set, so it'd be confusing.
> On Tue, Nov 8, 2016 at 7:30 AM, jeremy nagel <jeremymnagel at>
> wrote:
>> Hi,
>> was just chatting to colleagues about the utility of *const*. The fact
>> that it doesn't actually lead to immutable objects or arrays seems to make
>> it a bit toothless and misleading. Are there any proposals to have an
>> immutable version of const? I know you could use ImmutableJS but it would
>> be nice to have this part of the language.
>> Perhaps the keyword could be *final*.
>> cheers,
>> Jeremy
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