---
# System prepended metadata

title: 111th Meeting of TC39

---

# 111^th^ Meeting of TC39

- Agenda: https://github.com/tc39/agendas/blob/main/2025/11.md
- Reflector: https://github.com/tc39/Reflector/issues/564  (has notes and TCQ)

## Agenda key

When applicable, use these emoji as a prefix to the agenda item topic.

| Emoji | Meaning                                                              |
| :---: | :---                                                                 |
|  ❄️   | hard schedule constraints apply to this agenda item (e.g. presenter) |
|  🔒   | schedule constraints apply to this agenda item                       |
|  ⌛️   | late addition for stage advancement and/or schedule prioritization   |
|  🔁   | continuation of a previous agenda item                               |

## Day 1

<details>

<summary>10:00 to 15:00 Asia/Tokyo on Tuesday</summary>

### 10:00-12:00 (full)
    
- Opening & Welcome (10m, Rob Palmer)
  - Opening of the meeting
  - TC39 follows its Code of Conduct
  - Introduction of attendees
  - Host facilities, local logistics
  - Overview of communication tools
  - Quick recap of meeting IPR policy
  - Reminder to review GitHub Delegate teams (Jordan Harband)
  - <details>
        <summary>Note about meeting transcriptions</summary>
        A detailed transcript of the meeting is being prepared and will be eventually posted on GitHub. You may edit this at any time during the meeting in Google Docs for accuracy, including deleting comments which you do not wish to appear. You may also request corrections or deletions after the fact, by editing the Google Doc (in the first two weeks after the TC39 meeting) or subsequently making a PR in the notes repository or contacting the TC39 chairs.
    </details>
  - 🗒️ Call for note-takers
  - Adoption of the agenda
    - The agenda doth runneth over; please be mindful.
    - Presenters: please be on the lookout for messages from chairs; we may need to move topics forward if time frees up.
  - Approval of the minutes from last meeting
  - Next meeting host and logistics
- Secretary's Report (15m, Aki Rose Braun) ([slides](https://github.com/tc39/agendas/blob/main/2025/tc39-2025-049-Rev1.pdf))
- Project Editors’ Reports
  - [ECMA262](https://github.com/tc39/ecma262) Status Updates ([slides](https://docs.google.com/presentation/d/1OEO7E_2LAUA7EzH4v0JfTbq9-ro_05GEH_4lhserhGs/edit)) (5m, Kevin Gibbons)
  - [ECMA402](https://github.com/tc39/ecma402) Status Updates (5m, Ujjwal Sharma)
  - [ECMA404](https://www.ecma-international.org/publications/standards/Ecma-404.htm) Status Updates (1m, Chip Morningstar)
  - [Test262](https://github.com/tc39/test262) Status Updates (5m, Philip Chimento)
- Task Group Reports
  - TG3: Security (1m, Chris de Almeida)
  - TG4: Source Maps (5m, Nicolò Ribaudo)
  - TG5: Experiments in Programming Language Standardization (5m, Mikhail Barash)
- Updates from the [CoC Committee](https://tc39.es/code-of-conduct/#code-of-conduct-committee) (1m, Chris de Almeida)
- [Normative: In PluralRules, set compactDisplay only if notation is "compact"](https://github.com/tc39/ecma402/pull/1032) (10m, Frank Yung-Fong Tang)
- [Normative: make re-exporting a namespace object in 2 steps behave like 1 step](https://github.com/tc39/ecma262/pull/3715) / ([issue](https://github.com/tc39/ecma262/issues/3710), [slides](https://docs.google.com/presentation/d/1Ozx51idOUlBzJz8nPgvB8U5HypIN7o0w7mfEaL0xBSs/edit?usp=drivesdk)) (15m, Nicolò Ribaudo or Kevin Gibbons)
- [JSON.parse source text access](https://github.com/tc39/proposal-json-parse-with-source) for Stage 4 ([PR](https://github.com/tc39/ecma262/pull/3714)) (15m, Richard Gibson)
- [Temporal](https://github.com/tc39/proposal-temporal) status report and normative PR ([slides](https://ptomato.name/talks/tc39-2025-11)) (30m, Philip Chimento)
- [`Error.captureStackTrace`](https://github.com/tc39/proposal-error-capturestacktrace) for Stage 2 ([Slides](https://docs.google.com/presentation/d/1c3vpsgkUSD2qWCl_6RICnykWLYm2Tc7Dk_uusBKNvc8)) (45m, Daniel Minor)
- Intl Locale Info API for Stage 4 ([Slides](https://docs.google.com/presentation/d/17FKrRkWCfNdYui9uRQDRYzv2c3cOCp6ZM7Rly9MwGHM)) (30m, Frank Yung-Fong Tang)
- [Iterator Sequencing](https://github.com/tc39/proposal-iterator-sequencing) for Stage 4 ([slides](https://docs.google.com/presentation/d/1rOgJ2LY5IF4M6zXo_Cbn0HkTFlFceBrmEkvwKw-u3go), [PR](https://github.com/tc39/ecma262/pull/3713)) (12m, Michael Ficarra)

### Lunch (60 minutes)

### 13:00-15:00 (10m underflow)

- [Keep trailing zeros in Intl.NumberFormat and Intl.PluralRules](https://github.com/tc39/proposal-intl-keep-trailing-zeros) update ([slides](https://docs.google.com/presentation/d/1_xv96P0GaV2GZx4eevGd5GH9gvEBPbu9In6JA1WOOPg/edit?usp=sharing), [PR #10](https://github.com/tc39/proposal-intl-keep-trailing-zeros/pull/10), [issue #11](https://github.com/tc39/proposal-intl-keep-trailing-zeros/issues/11), [PR #12](https://github.com/tc39/proposal-intl-keep-trailing-zeros/pull/12)) (60m, Eemeli Aro)
- [Joint Iteration](https://github.com/tc39/proposal-joint-iteration) for Stage 3 ([tests PR](https://github.com/tc39/test262/pull/4609)) ([slides](https://docs.google.com/presentation/d/1ZB0Gf74zj_5ezC_iLfTlICDp862dLRdGdexHmekhJmg)) (20m, Michael Ficarra)
- [export defer](https://github.com/tc39/proposal-deferred-reexports) for Stage 2.7 ([slides](https://docs.google.com/presentation/d/1xB3qWhOX26dV3stpZ0bViVtMo711mtyCbBKUOLm3NW0/)) (30m, Nicolò Ribaudo)
- [Error.prototype.stack accessor](https://github.com/tc39/proposal-error-stack-accessor/issues/9) for stage 2.7 (30m, Jordan Harband)
- [Declarations in Conditionals](https://github.com/tc39/proposal-Declarations-in-Conditionals) for Stage 2 ([spec](https://tc39.es/proposal-Declarations-in-Conditionals/)) (30m, Devin Rousso)

### Mid-afternoon break (20 minutes)
    
### 15:20-17:00 (10m underflow)

- [`await` dictionary](https://github.com/tc39/proposal-await-dictionary/) for Stage 2 or 2.7 ([spec](https://tc39.es/proposal-await-dictionary/)) (30m, Ashley Claymore)
- [Intl Unit Protocol](https://github.com/sffc/proposal-intl-unit-protocol) for Stage 1 (30m, Shane F Carr)
- [Import Text](https://github.com/eemeli/proposal-import-text) for Stage 1, 2, or 2.7 ([slides](https://docs.google.com/presentation/d/1IMeeHjpUNZbrV7VTfgproPaht5dCeaeEFw8mE9tf7TE/edit?usp=sharing), [spec](https://eemeli.org/proposal-import-text/), [test262 PR](https://github.com/tc39/test262/pull/4607)) (30m, Eemeli Aro)
- TypedArray Concatenation for Stage 1 ([Slides](https://docs.google.com/presentation/d/1RIhMpf4gY2wX0KZcmCUU6i9l9Ay7WBu0vY4vIsJUwTg/edit?slide=id.p#slide=id.p)) (30m, James Snell)
- TypedArray Find Within for Stage 1 ([Slides](https://docs.google.com/presentation/d/1RIhMpf4gY2wX0KZcmCUU6i9l9Ay7WBu0vY4vIsJUwTg/edit?slide=id.g38e87ed9df8_0_0#slide=id.g38e87ed9df8_0_0)) (30m, James Snell)

</details>

## Day 2

<details>

<summary>10:00 to 15:00 Asia/Tokyo on Wednesday</summary>

### 10:00-12:00 (10m underflow)

- ❄️ [async iterator helpers](https://github.com/tc39/proposal-async-iterator-helpers/) recap/update/polyfill (30m, Kevin Gibbons)
- ❄️ [Iterator Join](https://github.com/bakkot/proposal-iterator-join) for stage 1, 2, or 2.7 ([spec](https://bakkot.github.io/proposal-iterator-join/), [slides](https://docs.google.com/presentation/d/1jclIOSbSdyepVCiYXQ4eXc2Uh8FBnBKnFOtsx12N3r0/edit?usp=sharing)) (20m, Kevin Gibbons)
- [Composites](https://github.com/tc39/proposal-composites/) comparator choice ([slides](https://docs.google.com/presentation/d/1ByfhAVVeEfeBj2g8TkP6f55hSmq8_8tevUxuRQLfISg/)) (60m, Ashley Claymore)
- ❄️ Decorators proposal status update? (20m, Jon Kuperman)

### Lunch (60 minutes)

### 13:00-15:00 (full)

- 🔒 [Concurrency Control](https://github.com/tc39/proposal-concurrency-control) Stage 1 updates ([slides](https://docs.google.com/presentation/d/1WoEqtVKEJgIhyTbOO2aWbNKLCFNPXHMb0ZW3gMFpyvU)) (60m, Michael Ficarra)
- [Object.propertyCount](https://github.com/tc39/proposal-object-property-count) for Stage 2 (30m, Ruben Bridgewater)
- WHATWG Stages ([slides](https://docs.google.com/presentation/d/1I-3g1QFGaiazy98hf0RisfH5f0BVn6SRH5lfxxXJ2g4/edit?usp=sharing)) (30m, Chengzhong Wu)

### Mid-afternoon break (20 minutes)
    
### 15:20-17:00 (15m overflow)

- Spec-defined or Implementation-defined limits? ([slides](https://docs.google.com/presentation/d/1NsezmIvFSr4qH4EXnh-cqOjikiUx196feKNM797m6fw/edit?slide=id.p#slide=id.p)) (45m, Shane F Carr)
- Module-declarations-like proposals in other areas of the web platform (20m, Nicolò Ribaudo)
- ❄️ [Comparisons](https://github.com/JakobJingleheimer/proposal-comparisons) for stage 1 ([slides](https://docs.google.com/presentation/d/1tu8yK57yMDdBsD4FgDX7GuRndLZfqvrukEG_AukYeJU/view)) (30m, Jacob Smith)

</details>

## Day 3

<details open>

<summary>10:00 to 15:00 Asia/Tokyo on Thursday</summary>

### 10:00-12:00 (full)

- ❄️ Intl Era Monthcode for Stage 3 [slides](https://notes.igalia.com/p/Lne8U2E5K#/) (30m, Ben Allen)
- ❄️ [Amount](https://github.com/tc39/proposal-amount) Stage 1 update ([spec](https://tc39.es/proposal-amount/)) (30m, Ben Allen)
- ❄️ [Intl Energy Units](https://github.com/johanrd/proposal-intl-energy-units) for Stage 1 (30m, Ben Allen)
- [Object.getNonIndexStringProperties](https://github.com/BridgeAR/array-get-non-index-string-properties) for Stage 1 or 2 (30m, Ruben Bridgewater)

### Lunch (60 minutes)

### 13:00-15:00 (full)

- 🔒 Class composition: Past, present, and future (60m, Lea Verou)
- [Class spread syntax](https://github.com/LeaVerou/proposal-class-spread) for Stage 1 (30m, Lea Verou)
- [Class field introspection](https://github.com/LeaVerou/proposal-class-field-introspection) for Stage 1 (30m, Lea Verou)

### Mid-afternoon break (20 minutes)
    
### 15:20-16:00 (full)

- 🔁 Continuation: [Declarations in Conditionals](https://github.com/tc39/proposal-Declarations-in-Conditionals) for Stage 2 ([spec](https://tc39.es/proposal-Declarations-in-Conditionals/)) (20m, Devin Rousso)
- 🔁 Continuation: [Composites](https://github.com/tc39/proposal-composites/) comparator choice ([slides](https://docs.google.com/presentation/d/1ByfhAVVeEfeBj2g8TkP6f55hSmq8_8tevUxuRQLfISg/)) (20m, Ashley Claymore)

</details>

***

## Overflow

### From agenda

### Timebox overrun

## Schedule constraints

- Jacob Smith is only available during the last hour of days one and two.
- Kevin Gibbons is only available before 16:00 JST (ideally 15:00) and would like to be present for the Concurrency Control item
- Ideally class composition open discussion should come right before class spread and fields introspection proposals, as they are highly related.
- Ben Allen is only available on Thursday.

<style>summary { font-weight: bold; }</style>