tc39

proposal-enum

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tc39 / proposal-enum

proposal-enum

Proposal for ECMAScript enums

Web Development

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5Mentions

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493GitHub stars

REPOSITORY AT A GLANCE

What to know before exploring

What it is

Proposal for ECMAScript enums

GitHub

Where it is used

No documented product use has been verified yet.

What people are saying

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Also in these discussions

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This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 1:49:46 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year5 dated mentions

Observed mentions: 2020-05-13 16:54:19 UTC to 2025-05-16 04:49:13 UTC.

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges

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Period	Start (UTC)	End (exclusive, UTC)	Mentions	Comments
2020	2020-01-01 00:00:00 UTC	2021-01-01 00:00:00 UTC	2	2
2021	2021-01-01 00:00:00 UTC	2022-01-01 00:00:00 UTC	0	0
2022	2022-01-01 00:00:00 UTC	2023-01-01 00:00:00 UTC	0	0
2023	2023-01-01 00:00:00 UTC	2024-01-01 00:00:00 UTC	1	1
2024	2024-01-01 00:00:00 UTC	2025-01-01 00:00:00 UTC	0	0
2025	2025-01-01 00:00:00 UTC	2026-01-01 00:00:00 UTC	2	2

What Hacker News says

5 sources

VoidWhisperer·May 16, 2025

Enums are possibly going to end up in JS eventually - this proposal[0] is at stage 1 (i know the readme says stage 0, it looks like there is a PR to update this). Granted, that means 'under consideration' but it is a start [0]: https://github.com/tc39/proposal-enum

In Teal – A statically-typed dialect of Lua

spankalee·Mar 2, 2025

Const objects really are better than enums, in every way except declaration brevity. They're erasable syntax, so they work in environments that just strip types. Their emit is just what you write without the types. They can be composed in a type-safe way with standard JS operations. You can still write JS docs for values, deprecated the, mark them as internal, etc. type ValueOf<T> = T[keyof T]; const Foo = { /** * A one digit * @deprecated */ one: '1', two: '2', three: '3' } as const; type Foo = ValueOf<typeof Foo>; const Bar = { blue: 'blue', } as const; type Bar = ValueOf<typeof Bar>; // You can union enum objects: const FooOrBar = {...Foo, ...Bar}; // And get union of their values: type FooOrBar = ValueOf<typeof FooOrBar>; const doSom

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ething = (foo: Foo) => {} // You can reference values just like enums: doSomething(Foo.two); // You can also type-safely reference enum values by their // key name: doSomething(Foo['two']); Given the TypeScript team's stance on new non-erasable syntax, I have to think this is how they would have gone if they had `as const` from the beginning. Ron Buckton of the TS team is championing an enum proposal for JS: https://github.com/rbuckton/proposal-enum Hopefully that goes somewhere and improves the declaration side of thigns too.

In An ode to TypeScript enums

WorldMaker·Mar 16, 2023

Enums have been proposed for JS for quite a while (there was a sort of enum in "the lost version" ES4 and a TC-39 proposal stuck in Stage 0 for years now [1]). Enums have always had relatively simple JS output that resembles a somewhat common pattern in JS. It was a "standard", just never really a deeply adopted "standard". What's today called "namespaces" in Typescript was originally called "modules" and then "inner modules" (to differentiate from "exterior modules") and is a tiny simplification on a JS pattern that was extremely common at the time of Typescript's inception called at the time "IIFE modules". "namespace" is a very C# name chosen in desperation (when it became clear that "exterior modules" were the present not just the future of the language and "interior modules" was too confusing a term to live), but it's a very old (and

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used to be extremely common) JS pattern that TS gave a tiny bit of syntax sugar to. It was a "standard" that existed at the time that was (rightfully) killed by AMD/UMD/CommonJS/ESM, but it is hard to fault the Typescript team at the early 0.x days thinking the "Stage Wild" JS pattern would possibly live on for many years to come. (This is also relevant to the patch notes for Typescript 5.0 as 5.0 is the first version [!] to itself be written as [proper/"exterior"] modules rather than namespaces. There are some interesting stories, including in these release notes for why that took so long to transition and what the performance benefits have been post-transition.) Even those things that didn't seem like ES standards have some history as JS "standards". It's not like TS 0.x/1.x didn't support "standards", it is more that the TS team mostly decided to focus more on later stage ES standards (more likely to be accepted by browsers) rather than trying to "prollyfill" Stage 0 and "Stage Wild" standards. [1] https://github.com/rbuckton/proposal-enum

In TypeScript 5.0

robpalmer·Nov 11, 2020

There isn't much of a difference between regular enum and const enum when it comes to the usage of the enum keyword. The big difference is what they compile to - where const enum evaporates by inlining the values into the usage sites. enum is a keyword that is reserved in ECMAScript and therefore may one day clash with TypeScript. It's unlikely any ECMAScript-defined semantics for enum would match today's TypeScript enum. So it's not on any standards track. There is already a proposal for JS enum that has different semantics to TS enum, and it was created by someone on the TypeScript team: https://github.com/rbuckton/proposal-enum So the const form doesn't really change the hazard.

In Insights from Adopting TypeScript at Scale

dfabulich·May 13, 2020

Does anybody here know where to go to have conversations with the TypeScript team about adding browser features to better support TypeScript? A lot was happening back in 2018. A Googler put together a proposal to add ignorable "pluggable" type annotations to JavaScript, which would allow browsers to run TypeScript directly without transpilation (and without type checking). https://github.com/samuelgoto/proposal-pluggable-types And a member of the TypeScript team at Microsoft put together a proposal to add enums to JS. https://github.com/rbuckton/proposal-enum Neither one of these seem to be active. What happened? What would it be like to get these landed?

In Announcing TypeScript 3.9