Agenda for the 105th meeting of Ecma TC39

September 24, 2025 · View on GitHub

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Agenda for the 105th meeting of Ecma TC39

  • Host: Remote
  • Dates and times:
    • 10:00 to 15:00 MST (America/Denver) on 2 December 2024
    • 10:00 to 15:00 MST (America/Denver) on 3 December 2024
    • 10:00 to 15:00 MST (America/Denver) on 4 December 2024
    • 10:00 to 15:00 MST (America/Denver) on 5 December 2024
  • Location: Albuquerque, New Mexico
  • Attendee information: https://github.com/tc39/Reflector/issues/545
  • Total duration of scheduled discussions: dynamically computed total of timeboxes on the agenda
gantt
  1 month before the meeting: milestone, 2024-11-02 10:00-0700, 1m
  Proposal advancement deadline: milestone, 2024-11-22 10:00-0700, 1m
  Schedule constraint deadline: milestone, 2024-11-29 10:00-0700, 1m
  Day 1 : day1, 2024-12-02 10:00-0700, 7h
  Day 2 : day2, 2024-12-03 10:00-0700, 7h
  Day 3 : day3, 2024-12-04 10:00-0700, 7h
  Day 4 : day4, 2024-12-05 10:00-0700, 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('2024-12-02T10:00[America/Denver]')
  .withTimeZone(Temporal.Now.timeZoneId()) // your time zone
  .toLocaleString();

Background:

Agenda topic rules

Deadline for advancement eligibility: November 22nd, 10:00 MST

  • 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 (slides) (15m, Samina Husain)

  7. Project Editors’ Reports

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

  8. Task Group Reports

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

  9. Updates from the CoC Committee (5m)

  10. Web compatibility issues / Needs Consensus PRs

    timeboxtopicpresenter
    10miterator helpers close receiver on argument validation failureKevin Gibbons
    30mre-using IteratorResult objects in iterator helpers (PR) (slides)Michael Ficarra

  11. Overflow from previous meeting

    timeboxtopicpresenter

  12. Short (≤30m) Timeboxed Discussions

    timeboxtopicpresenter
    1mCall for reviewers - ESM Phase ImportsGuy Bedford
    10mProcess document fixes and corrections: #46 and #48Chris de Almeida
    10mThe importance of supporting materials (slides)Daniel Minor
    30mBriefing on the formation and goals of TC55 (or, All About Moving the WinterCG into Ecma) (slides)James M Snell

  13. Proposals

    stagetimeboxtopicpresenter
    315mIntl.DurationFormat for Stage 4. (PR) (slides)Ben Allen
    2.715mError.isError to stage 3?Jordan Harband
    2.715miterator sequencing for Stage 3 (tests) (slides)Michael Ficarra
    2.740mimport defer updates (slides)Nicolò Ribaudo
    2.760mShadowRealm for Stage 3 (slides)Philip Chimento
    25mAsyncContext request for Stage 2.7 reviewers (Slides)Andreu Botella
    230mUpsert (formerly Map.emplace) Update and request for Stage 2 reviewers (Slides)Daniel Minor
    260mESM Phase Imports for Stage 2.7 (slides)Guy Bedford
    130mImmutable ArrayBuffer to stage 2 (slides.key, slides.pdf, docs slides)Mark Miller
    130mMeasure Stage 1 update (slides)Eemeli Aro
    160mError Stacks Structure for Stage 2Jordan Harband
    030mImport Sync discussion, request for Stage 1? (slides)Guy Bedford
    030mMore Currency Display Choices for Stage 1/2Eemeli Aro
    060mStabilize to stage 1 (youtube talk, slides.key, slides.pdf, docs slides)Mark Miller

  14. Longer or open-ended discussions

    timeboxtopicpresenter
    30mModule Harmony: where we are (slides)Nicolò Ribaudo
    60mVision for numeric types in ECMAScript (slides)Shane F. Carr

  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

  • Mark Miller: Monday 2 December will be hard for me to attend (due to travel). So at least my presentations will need to be elsewhen. I will be at all of the other days.
    • Would be good for my "Stabilize" to precede Nicolò's "import defer". (Already briefly discussed with Nicolo)
    • In decreasing priority order, I would like to be able to attend, so prefer any day other than Monday:
      • Module Harmony
      • Error Stack Structure
      • ShadowRealm
      • import defer
      • re-using Iterator Result objects
      • ESM Phase Sync
      • TC55 (moving WinterCG)
  • MF: the IteratorResult needs-consensus PR should be discussed before (though not necessarily immediately before) iterator sequencing Stage 3 advancement
  • Guy Bedford is unavailable the morning of December 3.
  • Shane Carr has personal family vacation on December 2-4 and would therefore prefer to present Vision for Numeric Types on December 5.
  • Matthew Gaudet would like to attend Error Stacks; 1-3pm is the best range for the duration of the meeting.
  • The Measure Stage 1 Update should be discussed after (though not necessarily immediately after) the Vision for numeric types in ECMAScript.

Late-breaking Schedule Constraints

  • Not super imortant, but if there is a choice it'd be great to have the "Module harmony" presentation before the other module presentations, as it gives a very high level overview.