#TC39
LightNews LightNews
robpalmer.bsky.social
More potential advancements:

2⃣ BigInt from exponential
2⃣ Composites
2⃣ Private Declarations
1⃣ Pulling in AbortController

The full agenda is here:

github.com/tc39/agendas...
agendas/2026/09.md at main · tc39/agendas
TC39 meeting agendas. Contribute to tc39/agendas development by creating an account on GitHub.
github.com
September 27, 2026 at 11:07 AM
jordan.har.band
`Error.isError` was just approved for stage 3 in today's @tc39.bsky.social!

- github.com/tc39/proposa...
- github.com/tc39/proposa...
- npmjs.com/error.iserror
`Error.isError` to stage 3, per 2024.12.02 TC39 · tc39/proposals@6db6ffb
github.com
December 2, 2024 at 6:55 PM
ashley-c.bsky.social
Just added Composites* for Stage 2 to the next TC39 agenda.

github.com/tc39/proposa...

Slides: docs.google.com/presentation...

PR: github.com/tc39/agendas...

*API name placeholder
GitHub - tc39/proposal-composites
Contribute to tc39/proposal-composites development by creating an account on GitHub.
github.com
August 11, 2026 at 5:12 PM
sebastienlorber.com
One of the most exciting JS proposals now has a draft spec

tc39.es/proposal-com...

Aiming for stage 2 at the next TC39 meeting

github.com/tc39/agendas...
September 1, 2026 at 5:22 PM
boshen.github.io
I am invited to tc39 as invited expert, representing tooling presence in the committee.
November 8, 2024 at 8:03 AM
robpalmer.bsky.social
ECMAScript excitement 😉

Congrats to @goose.icu on advancing the Math.clamp proposal to Stage 2 at TC39 today 🎉

Math.clamp(number, min, max) constrains the number to be between the stated range 👍

github.com/tc39/proposa...
GitHub - tc39/proposal-math-clamp: A TC39 proposal to add Math.clamp
A TC39 proposal to add Math.clamp. Contribute to tc39/proposal-math-clamp development by creating an account on GitHub.
github.com
May 29, 2025 at 3:07 PM
robpalmer.bsky.social
Future of the Web panel at @viteconf.org were asked about the most exciting upcoming web standards:

🔶 AsyncContext (@ryansolid.bsky.social)
github.com/tc39/proposa...

🔶 import defer (@evanyou.me)
github.com/tc39/proposa...

🔶 Module Declarations (@ryansolid.bsky.social)
github.com/tc39/proposa...
GitHub - tc39/proposal-async-context: Async Context for JavaScript
Async Context for JavaScript. Contribute to tc39/proposal-async-context development by creating an account on GitHub.
github.com
October 10, 2025 at 4:06 PM
robpalmer.bsky.social
ECMAScript excitement 😉

Congrats to my coworker @ashley-c.bsky.social at TechAtBloomberg on advancing Await Dictionary to Stage 3 at TC39 🎉

Promise.all returns positional results as an array. Promise.allKeyed allows named results inside an object 👍

github.com/tc39/proposa...
const { shape, color, mass, } = await Promise.allKeyed({ shape: getShape(), color: getColor(), mass: getMass(), });
July 27, 2026 at 7:34 AM
styfle.dev
I might have set a @tc39.es world record. I joined as a

* First time delegate at
* First plenary meeting pitching
* First proposal

And somehow went from Stage 0 to Stage 2 🚀

github.com/tc39/proposa...
GitHub - tc39/proposal-import-bytes: A modest proposal for importing bytes in javascript
A modest proposal for importing bytes in javascript - tc39/proposal-import-bytes
github.com
July 31, 2025 at 11:24 PM
joshuakgoldberg.com
I'm now an invited expert for TC39, around community+ecosystem tooling. Very excited to give perspective on great tools like linters to the committee.

Huge shoutout & thanks to @nicr.dev for pushing for my & other tooling folks to be involved in TC39! ❤️‍🔥
GitHub org invite notice: "You've been invited to the Ecma TC39 organization! Invited by Jordan Harband"
November 8, 2024 at 4:06 PM
tc39.es
Ecma International Excitement 🎉

Last week, two TC39 members, Rob Palmer (@robpalmer.bsky.social) and Michael Saboff, received the Ecma Recognition Award for their contributions to Ecma, including TC39.
July 3, 2025 at 9:26 PM
robpalmer.bsky.social
ECMAScript excitement 😉

Congrats to @ashley-c.bsky.social on advancing the Composites proposal to Stage 1 at TC39 today 🎉

This is the evolution of Stage 2 Record & Tuple which has now been withdrawn.

A key difference is that Composites are objects, not primitives.

github.com/tc39/proposa...
GitHub - tc39/proposal-composites
Contribute to tc39/proposal-composites development by creating an account on GitHub.
github.com
April 14, 2025 at 7:11 PM
robpalmer.bsky.social
ECMAScript excitement 😉

Congrats to Ujjwal Sharma on advancing Intl.DurationFormat to Stage 4 at TC39 today 🎉

Intl.DurationFormat enables language-sensitive duration formatting.

Example: 10000 seconds ➡️ 2 hours 46 minutes 40 seconds

github.com/tc39/proposa...
GitHub - tc39/proposal-intl-duration-format
Contribute to tc39/proposal-intl-duration-format development by creating an account on GitHub.
github.com
December 2, 2024 at 8:18 PM
robpalmer.bsky.social
ECMAScript excitement 😉

Congrats to @chronicles.org on meeting the conditions for Explicit Resource Management to be Stage 4 at @tc39.es today 🎉

It introduces `using` declarations and the Symbol.dispose protocol to deterministically and ergonomically release resources 👍

github.com/tc39/proposa...
GitHub - tc39/proposal-explicit-resource-management: ECMAScript Explicit Resource Management
ECMAScript Explicit Resource Management. Contribute to tc39/proposal-explicit-resource-management development by creating an account on GitHub.
github.com
May 20, 2026 at 12:52 AM
littledan.dev
The exciting future or Records & Tuples in JavaScript: github.com/tc39/proposa...

* Now they're objects called Composites, instead
* They're really just frozen Objects/Arrays!
* Except with an extra bit for Map/Set key behavior
* You need to call Composite.equals for comparison; === is by identity
2025 February TC39 presentation update · Issue #393 · tc39/proposal-record-tuple
At TC39 last week (2025/02) we discussed R&T. Slides here: https://docs.google.com/presentation/d/1uONn7T91lfZDV4frCsxpwd1QB_pU3P7F6V2j9jEPnA8/. Minutes are typically available three weeks after pl...
github.com
February 24, 2025 at 3:30 PM
robpalmer.bsky.social
ECMAScript excitement 😉

Congrats to @jordan.har.band on advancing the proposal for RegExp.escape to Stage 4 today at TC39 🎉

It lets you escape arbitrary strings so they can be used in Regular Expressions.

RegExp.escape("(*.*)"); // "\(\*\.\*\)"

github.com/tc39/proposa...
GitHub - tc39/proposal-regex-escaping: Proposal for investigating RegExp escaping for the ECMAScript standard
Proposal for investigating RegExp escaping for the ECMAScript standard - tc39/proposal-regex-escaping
github.com
February 18, 2025 at 7:30 PM
robpalmer.bsky.social
ECMAScript excitement 😉

Congrats to my coworker @ashley-c.bsky.social at TechAtBloomberg on advancing Await Dictionary to Stage 2.7 at TC39 today 🎉

Promise.all returns positional results as an array. Promise.allKeyed allows named results inside an object 👍

github.com/tc39/proposa...
const { shape, color, mass, } = await Promise.allKeyed({ shape: getShape(), color: getColor(), mass: getMass(), });
November 18, 2025 at 6:33 AM
robpalmer.bsky.social
ECMAScript excitement 😉

Congrats to @chronicles.org on advancing the Enum proposal to Stage 1 at TC39 today 🎉

This aims to bring the good parts of TypeScript enums to JavaScript plus enhancements such as new datatypes & potentially runtime performance improvements 👍

github.com/tc39/proposa...
GitHub - tc39/proposal-enum: Proposal for ECMAScript enums
Proposal for ECMAScript enums. Contribute to tc39/proposal-enum development by creating an account on GitHub.
github.com
April 15, 2025 at 4:20 PM
thealexlichter.com
I am having to honor to join this weeks 114th @tc39.es meeting as observer! 🎉
Badge of the 114th TC39 meeting (hosted at JetBrains) with my name + VoidZero as company on it.
May 21, 2026 at 8:28 AM
robpalmer.bsky.social
ECMAScript excitement 😉

Congrats to @tabatkins.com on advancing the Seeded Pseudo-Random Numbers proposal to Stage 2 at TC39 today 🎉

It produces a series of pseudo-random numbers in a way that can be reproduced across program runs and different JS realms 👍

github.com/tc39/proposa...
GitHub - tc39/proposal-seeded-random: Proposal for a new SeededPRNG class that yields reproducible sequences of random numbers.
Proposal for a new SeededPRNG class that yields reproducible sequences of random numbers. - tc39/proposal-seeded-random
github.com
May 29, 2025 at 1:51 PM
sebastienlorber.com
TIL about the JS "Declarations in Conditionals" proposal

This lets you write const/let inside if/while block

Curious, would you use this?
I think I like it, could make code slightly less verbose and still explicit

(TC39 stage 1, will be presented for stage 2 next week)

github.com/tc39/proposa...
November 10, 2025 at 5:01 PM
webdevs.firefox.com
JavaScript declarations in conditionals was discussed at TC39 recently, but consensus broke down over one key detail. How do you think it should behave?
December 15, 2025 at 3:19 PM
robpalmer.bsky.social
ECMAScript excitement 😉

Congrats to Dan Minor @mozilla.org on advancing Error.captureStackTrace to Stage 2 at TC39 today 🎉

This is about standardizing and potentially normalizing an API that already exists.

github.com/tc39/proposa...
GitHub - tc39/proposal-error-capturestacktrace: Standardizing Error.captureStackTrace
Standardizing Error.captureStackTrace. Contribute to tc39/proposal-error-capturestacktrace development by creating an account on GitHub.
github.com
November 18, 2025 at 2:47 AM
robpalmer.bsky.social
ECMAScript excitement 😉

Sony Interactive Entertainment will host this week's TC39 meeting in Tokyo. Potential advancements:

4⃣ Dynamic Code Brand Checks
4⃣ Iterator Chunking/Includes/Join
3⃣ Thenable Curtailment
2⃣.7⃣ default in export *
2⃣.7⃣ export defer
2⃣.7⃣ JSON.parse opts
🧵
September 27, 2026 at 11:07 AM
tc39.es
ECMAScript Excitement 🎉

Today, TC39 advanced these proposals:

2️⃣.7️⃣ Upsert
1️⃣ Composite Keys

and withdrew Records & Tuples
April 14, 2025 at 8:43 PM