Agenda for the 102nd meeting of Ecma TC39

September 24, 2025 · View on GitHub

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Agenda for the 102nd meeting of Ecma TC39

  • Host: Mozilla & Aalto University
  • Dates and times:
    • 10:00 to 17:00 EEST (Europe/Helsinki) on 11 June 2024
    • 10:00 to 17:00 EEST (Europe/Helsinki) on 12 June 2024
    • 10:00 to 16:00 EEST (Europe/Helsinki) on 13 June 2024
  • Location: Helsinki, Finland
  • Attendee information: https://github.com/tc39/Reflector/issues/527
gantt
  1 month before the meeting: milestone, 2024-05-11 10:00+0300, 1m
  Proposal advancement deadline: milestone, 2024-06-01 10:00+0300, 1m
  Schedule constraint deadline: milestone, 2024-06-08 10:00+0300, 1m
  Day 1 : day1, 2024-06-11 10:00+0300, 8h
  Day 2 : day2, 2024-06-12 10:00+0300, 8h
  Day 3 : day3, 2024-06-13 10:00+0300, 8h
  todayMarker stroke-width:5px,str3ke:#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('2024-06-11T10:00[Europe/Helsinki]')
  .withTimeZone(Temporal.Now.timeZoneId()) // your time zone
  .toLocaleString();

Background:

Agenda topic rules

Deadline for advancement eligibility: June 1st, 10:00 EEST

  • 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 (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)
    3. TG5: Experiments in Programming Language Standardization (slides) (5m, Mikhail Barash)

  9. Updates from the CoC Committee (5m)

  10. Web compatibility issues / Needs Consensus PRs

    timeboxtopicpresenter
    20mECMA-402 PR #877: Specify time zone IDs to reduce divergence between engines (slides)Justin Grant

  11. Overflow from previous meeting

    timeboxtopicpresenter
    15m⌛️🔁 Continuation from previous meeting: Explicit Resource Management Normative Updates and Needs Consensus PRs (slides, PRs)Ron Buckton

  12. Short (≤30m) Timeboxed Discussions

    timeboxtopicpresenter
    10mStatus of TCQ reloadedChristian Ulbrich
    30mNova JavaScript Engine - Exploring a data-oriented engine designAapo Alasuutari

  13. Proposals

    stagetimeboxtopicpresenter
    35meval() changes for trusted types update (description)Nicolò Ribaudo
    315mAvoid second pass/buffer in base64 setFromBase64/setFromHex methods (issue, PR)Kevin Gibbons
    315mOption to omit padding in toBase64 (issue, PR)Kevin Gibbons
    330mIntl.DurationFormat Stage 3 update and normative PRs (slides)Ben Allen
    390mTemporal Stage 3 update and scope reduction (slides)Philip Chimento
    2.7<5mShadowRealm status FYI (slide)Philip Chimento
    2.715mPromise.try for stage 3 (tests)Jordan Harband
    230mRegExp.escape question, and for stage 2.7?Jordan Harband
    230mDeferred import evaluation for Stage 2.7 (slides)Nicolò Ribaudo
    245mjoint iteration for Stage 2.7 (slides)Michael Ficarra
    245mAsync iterators update (slides)Kevin Gibbons
    115mAtomics.pause for stage 2 or 2.7Shu-yu Guo
    130mError.isError for stage 2Jordan Harband
    130mESM Phase Imports for stage 2 (slides)Guy Bedford
    130miterator sequencing for Stage 2 (slides)Michael Ficarra
    130mIntl.MessageFormat Stage 1 open question involving error handling design patterns (slides)Shane F. Carr
    160mShared struct discussion around methods (slides)Shu-yu Guo
    160mDecimal for stage 2 (slides)Jesse Alama
    115m⌛️ Discard Bindings update or stage 2 (slides, spec)Ron Buckton

  14. Longer or open-ended discussions

    timeboxtopicpresenter
    15m⌛️ Cancellation: Room for improvement (slides)Daniel Ehrenberg and Ron Buckton
    60mSource maps progress update (slides)Jonathan Kuperman and Agata Belkius
    60mSmart units progress update (slides)Ben Allen
    60m⌛️ Scrub of less active TC39 proposalsDaniel Ehrenberg
    60m⌛️ Algorithms for Signals (slides)Daniel Ehrenberg

  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

  • Jordan Harband is only available either the first two hours of each day, or the last two hours of each day; whichever is easier for the chairs to arrange. He would like to be present for his own items, as well as Decimal, Temporal, and Joint Iteration.
  • Guy Bedford is only available on Thursday the 13th.
  • Shu-yu Guo is only available for the last two hours on June 12 or June 13.
  • Sean Burke is only available for the last two hours of the day and would like to be present for the Temporal update.

Late-breaking Schedule Constraints

  • Ron Buckton will not be available on day 1 but would like to be present for the shared structs topic.
  • Ben Allen will not be available on day 1 — flight was delayed — and cannot present on Intl.DurationFormat on that day.