The full agenda including links to the slides and presentation materials can be found here.
Full meeting notes will be published in roughly two weeks time.
github.com/tc39/agendas...
Full meeting notes will be published in roughly two weeks time.
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
October 1, 2026 at 8:44 AM
The full agenda including links to the slides and presentation materials can be found here.
Full meeting notes will be published in roughly two weeks time.
github.com/tc39/agendas...
Full meeting notes will be published in roughly two weeks time.
github.com/tc39/agendas...
The 116th meeting of @tc39.es was hosted by Sony Interactive Entertainment in Tokyo.
Thanks to our hosts for again providing an excellent venue, facilities, refreshments, dedicated artwork(!), and an excellent events team 👍
Thanks to our hosts for again providing an excellent venue, facilities, refreshments, dedicated artwork(!), and an excellent events team 👍
October 1, 2026 at 8:44 AM
The 116th meeting of @tc39.es was hosted by Sony Interactive Entertainment in Tokyo.
Thanks to our hosts for again providing an excellent venue, facilities, refreshments, dedicated artwork(!), and an excellent events team 👍
Thanks to our hosts for again providing an excellent venue, facilities, refreshments, dedicated artwork(!), and an excellent events team 👍
ECMAScript excitement 😉
This week @tc39.es advanced these proposals 🎉
4️⃣ Dynamic Code Brand Checks
4️⃣ Iterator Chunking/Includes/Join
3️⃣ Thenable Curtailment
2️⃣.7️⃣ default in export * from "mod"
2️⃣.7️⃣ export defer
2️⃣.7️⃣ JSON.parse options
2️⃣ BigInt from Exponential
2️⃣ Composites
1️⃣ Pulling in AbortController
This week @tc39.es advanced these proposals 🎉
4️⃣ Dynamic Code Brand Checks
4️⃣ Iterator Chunking/Includes/Join
3️⃣ Thenable Curtailment
2️⃣.7️⃣ default in export * from "mod"
2️⃣.7️⃣ export defer
2️⃣.7️⃣ JSON.parse options
2️⃣ BigInt from Exponential
2️⃣ Composites
1️⃣ Pulling in AbortController
October 1, 2026 at 8:44 AM
ECMAScript excitement 😉
This week @tc39.es advanced these proposals 🎉
4️⃣ Dynamic Code Brand Checks
4️⃣ Iterator Chunking/Includes/Join
3️⃣ Thenable Curtailment
2️⃣.7️⃣ default in export * from "mod"
2️⃣.7️⃣ export defer
2️⃣.7️⃣ JSON.parse options
2️⃣ BigInt from Exponential
2️⃣ Composites
1️⃣ Pulling in AbortController
This week @tc39.es advanced these proposals 🎉
4️⃣ Dynamic Code Brand Checks
4️⃣ Iterator Chunking/Includes/Join
3️⃣ Thenable Curtailment
2️⃣.7️⃣ default in export * from "mod"
2️⃣.7️⃣ export defer
2️⃣.7️⃣ JSON.parse options
2️⃣ BigInt from Exponential
2️⃣ Composites
1️⃣ Pulling in AbortController
Technically it's a shallow comparison. But if the children are all composites or primitives, that ends up being equivalent to a deep comparison.
The comparison would fail if it hits two independent objects that have equivalent children.
github.com/tc39/proposa...
The comparison would fail if it hits two independent objects that have equivalent children.
github.com/tc39/proposa...
GitHub - tc39/proposal-composites
Contribute to tc39/proposal-composites development by creating an account on GitHub.
github.com
October 1, 2026 at 5:49 AM
Technically it's a shallow comparison. But if the children are all composites or primitives, that ends up being equivalent to a deep comparison.
The comparison would fail if it hits two independent objects that have equivalent children.
github.com/tc39/proposa...
The comparison would fail if it hits two independent objects that have equivalent children.
github.com/tc39/proposa...
Los iteradores de #JavaScript ya tienen join(), includes(), chunks() y windows(): el #TC39 los pasó a stage 4 y entran en ECMAScript 2027.
Como son perezosos, procesas muchos datos sin cargarlo todo en memoria. Ya me veo usando chunks() para mandar peticiones a #LLM en lotes.
Como son perezosos, procesas muchos datos sin cargarlo todo en memoria. Ya me veo usando chunks() para mandar peticiones a #LLM en lotes.
September 30, 2026 at 2:41 PM
Los iteradores de #JavaScript ya tienen join(), includes(), chunks() y windows(): el #TC39 los pasó a stage 4 y entran en ECMAScript 2027.
Como son perezosos, procesas muchos datos sin cargarlo todo en memoria. Ya me veo usando chunks() para mandar peticiones a #LLM en lotes.
Como son perezosos, procesas muchos datos sin cargarlo todo en memoria. Ya me veo usando chunks() para mandar peticiones a #LLM en lotes.
¡JavaScript sigue evolucionando! Prepara objetos que se comparan por valor.
Composites avanza a Stage 2 en TC39.
Dos objetos con el mismo contenido podrán ser === aunque se creen por separado.
También funciona por valor en Set y como llave de Map.
Composites avanza a Stage 2 en TC39.
Dos objetos con el mismo contenido podrán ser === aunque se creen por separado.
También funciona por valor en Set y como llave de Map.
September 30, 2026 at 2:04 PM
¡JavaScript sigue evolucionando! Prepara objetos que se comparan por valor.
Composites avanza a Stage 2 en TC39.
Dos objetos con el mismo contenido podrán ser === aunque se creen por separado.
También funciona por valor en Set y como llave de Map.
Composites avanza a Stage 2 en TC39.
Dos objetos con el mismo contenido podrán ser === aunque se creen por separado.
También funciona por valor en Set y como llave de Map.
ECMAScript excitement 😉
Congrats to @ashley-c.bsky.social from TechAtBloomberg on advancing the Composites proposal to Stage 2 at @tc39.es today 🎉
Composites are objects that are compared by value instead of identity. They are an evolution of Record & Tuple proposal.
Congrats to @ashley-c.bsky.social from TechAtBloomberg on advancing the Composites proposal to Stage 2 at @tc39.es today 🎉
Composites are objects that are compared by value instead of identity. They are an evolution of Record & Tuple proposal.
September 30, 2026 at 8:15 AM
ECMAScript excitement 😉
Congrats to @ashley-c.bsky.social from TechAtBloomberg on advancing the Composites proposal to Stage 2 at @tc39.es today 🎉
Composites are objects that are compared by value instead of identity. They are an evolution of Record & Tuple proposal.
Congrats to @ashley-c.bsky.social from TechAtBloomberg on advancing the Composites proposal to Stage 2 at @tc39.es today 🎉
Composites are objects that are compared by value instead of identity. They are an evolution of Record & Tuple proposal.
🗼 Live from the @tc39.es plenary in Tokyo: Just resolved to advance github.com/tc39/proposa... to Stage 2.7
Soon, export * from "foo" will also re-export default. 🤯
Chuckling to myself thinking how this would have likely been a non-starter in a more compat risk-averse committee (e.g. WHATWG). 🙃
Soon, export * from "foo" will also re-export default. 🤯
Chuckling to myself thinking how this would have likely been a non-starter in a more compat risk-averse committee (e.g. WHATWG). 🙃
GitHub - tc39/proposal-export-star-default: Proposal to include default export in `export * from 'module'`
Proposal to include default export in `export * from 'module'` - tc39/proposal-export-star-default
github.com
September 30, 2026 at 7:31 AM
🗼 Live from the @tc39.es plenary in Tokyo: Just resolved to advance github.com/tc39/proposa... to Stage 2.7
Soon, export * from "foo" will also re-export default. 🤯
Chuckling to myself thinking how this would have likely been a non-starter in a more compat risk-averse committee (e.g. WHATWG). 🙃
Soon, export * from "foo" will also re-export default. 🤯
Chuckling to myself thinking how this would have likely been a non-starter in a more compat risk-averse committee (e.g. WHATWG). 🙃
It feels very strange for me that I can hear TC39 meeting news during the day in Japan time
September 30, 2026 at 7:04 AM
It feels very strange for me that I can hear TC39 meeting news during the day in Japan time
ECMAScript excitement 😉
Congrats to Richard Gibson on advancing BigInt from Exponential to Stage 2 at @tc39.es today 🎉
🔶 BigInt("1e2")
It allows a BigInt to be created from a number that includes an exponential component 👍
Congrats to Richard Gibson on advancing BigInt from Exponential to Stage 2 at @tc39.es today 🎉
🔶 BigInt("1e2")
It allows a BigInt to be created from a number that includes an exponential component 👍
September 30, 2026 at 3:17 AM
ECMAScript excitement 😉
Congrats to Richard Gibson on advancing BigInt from Exponential to Stage 2 at @tc39.es today 🎉
🔶 BigInt("1e2")
It allows a BigInt to be created from a number that includes an exponential component 👍
Congrats to Richard Gibson on advancing BigInt from Exponential to Stage 2 at @tc39.es today 🎉
🔶 BigInt("1e2")
It allows a BigInt to be created from a number that includes an exponential component 👍
ECMAScript excitement 😉
Congrats to @peet.bsky.social from TechAtBloomberg advancing JSON.parse Options to Stage 2.7 at @TC39 today 🎉
There are two independent opt-ins.
🔶 deep freezing the entire object
🔶 non-array objects get a null prototype
Names may change ⚠️
Congrats to @peet.bsky.social from TechAtBloomberg advancing JSON.parse Options to Stage 2.7 at @TC39 today 🎉
There are two independent opt-ins.
🔶 deep freezing the entire object
🔶 non-array objects get a null prototype
Names may change ⚠️
September 30, 2026 at 2:55 AM
ECMAScript excitement 😉
Congrats to @peet.bsky.social from TechAtBloomberg advancing JSON.parse Options to Stage 2.7 at @TC39 today 🎉
There are two independent opt-ins.
🔶 deep freezing the entire object
🔶 non-array objects get a null prototype
Names may change ⚠️
Congrats to @peet.bsky.social from TechAtBloomberg advancing JSON.parse Options to Stage 2.7 at @TC39 today 🎉
There are two independent opt-ins.
🔶 deep freezing the entire object
🔶 non-array objects get a null prototype
Names may change ⚠️
ECMAScript excitement 😉
Congrats to @michael.ficarra.me on advancing the Iterator Chunking proposal to Stage 4 at @tc39.es today 🎉
It can make iterators that chunk & window content.
[0,1,2,3].values().chunks(2); // [0,1], [2,3]
[0,1,2,3].values().windows(2); // [0,1], [1,2], [2,3]
Congrats to @michael.ficarra.me on advancing the Iterator Chunking proposal to Stage 4 at @tc39.es today 🎉
It can make iterators that chunk & window content.
[0,1,2,3].values().chunks(2); // [0,1], [2,3]
[0,1,2,3].values().windows(2); // [0,1], [1,2], [2,3]
September 29, 2026 at 5:28 AM
ECMAScript excitement 😉
Congrats to @michael.ficarra.me on advancing the Iterator Chunking proposal to Stage 4 at @tc39.es today 🎉
It can make iterators that chunk & window content.
[0,1,2,3].values().chunks(2); // [0,1], [2,3]
[0,1,2,3].values().windows(2); // [0,1], [1,2], [2,3]
Congrats to @michael.ficarra.me on advancing the Iterator Chunking proposal to Stage 4 at @tc39.es today 🎉
It can make iterators that chunk & window content.
[0,1,2,3].values().chunks(2); // [0,1], [2,3]
[0,1,2,3].values().windows(2); // [0,1], [1,2], [2,3]
ECMAScript excitement 😉
Congrats to @bakkot.com on advancing Iterator Join to Stage 4 at @tc39.es today 🎉
Iterator.prototype.join() turns an iterator directly into a single string (with an optional separator) just like Array.prototype.join()
github.com/tc39/proposa...
Congrats to @bakkot.com on advancing Iterator Join to Stage 4 at @tc39.es today 🎉
Iterator.prototype.join() turns an iterator directly into a single string (with an optional separator) just like Array.prototype.join()
github.com/tc39/proposa...
GitHub - tc39/proposal-iterator-join: JS proposal for a means to concatenate the contents of an iterator into a string
JS proposal for a means to concatenate the contents of an iterator into a string - tc39/proposal-iterator-join
github.com
September 29, 2026 at 4:37 AM
ECMAScript excitement 😉
Congrats to @bakkot.com on advancing Iterator Join to Stage 4 at @tc39.es today 🎉
Iterator.prototype.join() turns an iterator directly into a single string (with an optional separator) just like Array.prototype.join()
github.com/tc39/proposa...
Congrats to @bakkot.com on advancing Iterator Join to Stage 4 at @tc39.es today 🎉
Iterator.prototype.join() turns an iterator directly into a single string (with an optional separator) just like Array.prototype.join()
github.com/tc39/proposa...
LLM-Wiki for TC39 Meetings (Jxck) #tng48
https://www.docswell.com/s/jxck/K3JDML-llm-wiki-for-tc39-meetings
https://www.docswell.com/s/jxck/K3JDML-llm-wiki-for-tc39-meetings
LLM-Wiki for TC39 Meetings | ドクセル
TC39 x Meguro.es x JSConf.jp [Node gakuen 48th] - connpass #tng48 https://nodejs.connpass.com/event/...
www.docswell.com
September 28, 2026 at 1:33 PM
LLM-Wiki for TC39 Meetings (Jxck) #tng48
https://www.docswell.com/s/jxck/K3JDML-llm-wiki-for-tc39-meetings
https://www.docswell.com/s/jxck/K3JDML-llm-wiki-for-tc39-meetings
Hailing from Vancouver, now lives in Holland. He is a core collaborator of @nodejs.org (loaders/modules, test runner, and userland migrations teams), TC39 and WinterTC / TC55 delegate, and author of several npm packages. Outside of engineering, he's known for cats, wine, and brunch.
September 28, 2026 at 9:14 AM
Hailing from Vancouver, now lives in Holland. He is a core collaborator of @nodejs.org (loaders/modules, test runner, and userland migrations teams), TC39 and WinterTC / TC55 delegate, and author of several npm packages. Outside of engineering, he's known for cats, wine, and brunch.
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...
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
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...
2⃣ BigInt from exponential
2⃣ Composites
2⃣ Private Declarations
1⃣ Pulling in AbortController
The full agenda is here:
github.com/tc39/agendas...