Agenda for the 108th meeting of Ecma TC39

September 24, 2025 · View on GitHub

Ecma logo

Agenda for the 108th meeting of Ecma TC39

  • Host: Igalia
  • Dates and times:
    • 10:00 to 17:00 CEST (Europe/Madrid) on 28 May 2025
    • 10:00 to 17:00 CEST (Europe/Madrid) on 29 May 2025
    • 10:00 to 16:00 CEST (Europe/Madrid) on 30 May 2025
  • Location: A Coruña, Galicia
  • Attendee information: https://github.com/tc39/Reflector/issues/558
  • Total duration of scheduled discussions: dynamically computed total of timeboxes on the agenda
gantt
  1 month before the meeting: milestone, 2025-04-30 10:00+0200, 1m
  Proposal advancement deadline: milestone, 2025-05-16 10:00+0200, 1m
  Schedule constraint deadline: milestone, 2025-05-25 10:00+0200, 1m
  Day 1 : day1, 2025-05-28 10:00+0200, 8h
  Day 2 : day2, 2025-05-29 10:00+0200, 8h
  Day 3 : day3, 2025-05-30 10:00+0200, 7h
  todayMarker stroke-width:5px,stroke:#0f0,opacity:0.5

For meeting times in your timezone, visit Temporal docs and run the code below in the devtools console.

Temporal.ZonedDateTime.from('2025-05-28T10:00[Europe/Madrid]')
  .withTimeZone(Temporal.Now.timeZoneId()) // your time zone
  .toLocaleString();

Background:

Agenda topic rules

Deadline for advancement eligibility: May 16th 10:00 CEST

  • Note: this time is selected to be precisely 10 days prior to the start of the meeting
  1. Proposals not looking to advance may be added at any time; if after the deadline, please always use a pull request so that members are notified of changes. Note: an unmerged PR counts as “added” for the purposes of this requirement.
  2. Proposals seeking feedback at stage 0 must be added (and noted as such) prior to the deadline, or else delegates may object to advancement solely on the basis of missing the deadline.
    1. Such proposals should include supporting materials when possible.
  3. Proposals looking to advance to stage 1 must be added (and noted as such) prior to the deadline, or else delegates may object to advancement solely on the basis of missing the deadline.
    1. Such proposals must link to a proposal repository and they should link to supporting materials when possible.
  4. Proposals looking to advance to stages 2, 2.7, 3, or 4, as well as other normative changes to the standard or proposals in stage 3 or later looking to achieve consensus, must be added (and noted as such) along with links to the supporting materials prior to the deadline, or else delegates may withhold consensus for advancement solely on the basis of missing the deadline.
    1. If the supporting materials change substantially after the deadline, delegates may withhold consensus for advancement, based on the committee’s judgment.
    2. For urgent normative changes, the committee is expected to be more forgiving of a missed deadline, since there is generally less material to review than in a stage advancement.
    3. Proposals looking to advance to stage 4 must link to a pull request into the spec, since the process requires one.
  5. Proposal-based agenda items should be sorted primarily by stage (descending), secondarily by timebox (ascending), and finally by insertion date.

Supporting materials includes slides, a link to the proposal repository, a link to spec text, etc.; essentially, anything you are planning to present to the committee, or that would be useful for delegates to review.

Agenda key

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

EmojiMeaning
❄️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

Agenda items

  1. Opening, welcome and roll call (Chair)

    1. Opening of the meeting
    2. TC39 follows its Code of Conduct
    3. Introduction of attendees
    4. Host facilities, local logistics
    5. Quick recap of meeting IPR policy
    6. Overview of communication tools
    7. Reminder to review Github Delegate teams (Jordan Harband)
    8. TC39 stenography support and legal disclaimer

  2. Find volunteers for note taking

  3. Adoption of the agenda

  4. Approval of the minutes from last meeting

  5. Next meeting host and logistics

  6. Secretary's Report (15m, Samina Husain Slides)

  7. Project Editors’ Reports

    1. ECMA262 Status Updates (slides) (15m)
    2. ECMA402 Status Updates (slides) (15m)
    3. ECMA404 Status Updates (15m)
    4. Test262 Status Updates (15m)

  8. Task Group Reports

    1. TG3: Security (5m)
    2. TG4: Source Maps (5m) (slides)
    3. TG5: Experiments in Programming Language Standardization (5m)

  9. Updates from the CoC Committee (5m)

  10. Web compatibility issues / Needs Consensus PRs

    timeboxtopicpresenter
    10mNormative: Add "Late Errors for Function Call Assignment Targets" to Annex B (#3568, slides)Ross Kirsling
    10mNormative: Added note about sets of locales for web browser implementations needing to not change as a result of user behaviour (ecma402#780) (slides)Ujjwal Sharma
    10mNormative: Add 8 new numbering systems for Unicode 16 (ecma402#929)Ujjwal Sharma
    30mNormative: Add Intl.Locale.prototype.variants (ecma402#960, slides)Richard Gibson

  11. Overflow from previous meeting

    timeboxtopicpresenter

  12. Short (≤30m) Timeboxed Discussions

    timeboxtopicpresenter
    30mProposed change to the agenda deadlineChris de Almeida
    30mMaintaining Proposal Topics (slides)Mikhail Barash, J. S. Choi, Michael Ficarra
    30mMoving TCQ forward (repo)Christian Ulbrich

  13. Proposals

    stagetimeboxtopicpresenter
    320mIntl Locale Info Stage 3 Update: Normative: Return undefined if direction is unknown (SlidesShane F Carr
    315mError.isError for Stage 4Jordan Harband
    315mExplicit Resource Management for Stage 4 (spec pr, slides)Ron Buckton
    320mTemporal status update and normative change (slides)Philip Chimento
    330mArray.fromAsync for Stage 4 (spec pull request, slides)J. S. Choi
    2.730mImmutable ArrayBuffer for stage 3 (slides coming)Peter Hoddie, Richard Gibson
    2.730mIterator Sequencing for Stage 3 (slides)Michael Ficarra
    230mIterator Chunking for Stage 2.7 (slides)Michael Ficarra
    260mAsyncContext web integration brainstorming (slides)Andreu Botella
    130mDecimal stage 1 update (slides)Jesse Alama
    130mSeededPRNG for stage 2 (slides)Tab Atkins-Bittner
    130mMath.clamp for Stage 2 or 2.7 (slides)Oliver Medhurst
    160mIDL for ECMAScript with WebIDL (issue, slides)Arai
    030mKeep trailing zeros in Intl.NumberFormat and Intl.PluralRules for Stage 1 (slides)Eemeli Aro
    030mMore Random Functions for Stage 1 (slides)Tab Atkins-Bittner
    060mComparisons (né "Assertions") for Stage 1 (slides) (slides - updated)Jacob Smith

  14. Longer or open-ended discussions

    timeboxtopicpresenter
    60mECMA Framework SlidesSamina Husain
    90mJS numerics breakout session (Friday)Jesse Alama

  15. Overflow from timeboxed agenda items (in insertion order)

    topicpresenter

  16. Incubation call chartering (15m on the last day)

  17. Other business

    1. Thank host

  18. Adjournment

Schedule constraints

Schedule constraints should be supplied here as soon as possible, and at least three days before the meeting begins so that the Chairs can take them into account when preparing the schedule.

Normal Constraints

  • Samina would prefer the "ECMA Framework" topic to be discussed on Day 2 to give people time to mull it over and bring any questions or doubts the following day.
  • J. S. Choi is unavailable until 15:00 (GMT+2) on all days and would strongly prefer 05-28 or 05-29 over 05-30.
  • Peter Hoddie is available for the last two hours of each day and would like to be present for the Immutable ArrayBuffer topic and all entropy-related topics.
  • Ron Buckton is only available the last two hours of each day and would like to be present for Assertions.
  • Jesse Alama would prefer that the decimal update be presented after Eemeli Aro's "keep trailing zeroes", even though the former is at stage 1 and the latter is at stage 0.
  • Jordan Harband will only be at the last 2 hours of each day, and would like to be present for: Error.isError, SeededPRNG, Assertions, Math.clamp, Iterator chunking, deadline change, Iterator sequencing
  • Tab Atkins-Bittner is not available the last hour of each day (16:00 to 17:00), as that's "make breakfast/lunch for the wife" time, so don't schedule their topics (SeededPRNG, More Random Functions) then.
  • Richard Gibson strongly prefers the last 3 hours of each day, and would like to be present for: Intl.Locale.prototype.variants, Temporal, Immutable ArrayBuffer, Iterator Sequencing, Iterator Chunking

Late-breaking Schedule Constraints

  • Michal Mocny would like to attend the AsyncContext discussion at Day 1, 1300.