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Agenda for the 58th meeting of Ecma TC39

  • Host: Google, New York, NY
  • Dates: 23-25 May 2017
  • Times:
    • 10:00 to 17:00 ET on 23 and 24 of May 2017
    • 10:00 to 16:00 ET on 25 of May 2017
  • Location: 76 9th Avenue, New York, NY 1011, 16th street and 9th avenue
  • Wifi: GoogleGuest (no password)
  • Dinner: Wednesday, 18:30, at Buddakan
  • Contact: Domenic Denicola,, +1-408-355-4559


Please arrive at the 16th street entrance to the 76 9th Avenue building, at 16th Street and 9th Avenue. Badges should be available, as well as a Googler to escort you to the meeting room.

Allen's paper on standards committee participation for new attendees:




  • Near the office
  • Anything near an L or A/C/E subway stop will also work nicely

Agenda items

  1. Opening, welcome and roll call
  2. Opening of the meeting (Chair)
  3. Introduction of attendees
  4. Host facilities, local logistics
  5. Find volunteers for note taking lol
  6. Adoption of the agenda
  7. (Thursday) Approval of the minutes from last meeting (
  8. (Thursday) Report from the Ecma Secretariat (15m)
  9. ECMA262 Status Updates (15m)
  10. ECMA402 Status Updates (15m)
  11. (Thursday) ECMA404 (JSON) ISO fast-track. Review/approve disposition of comments responses and 404 2nd edition draft. (30m) Documents TC39-2017-016, TC39-2017-017 (pdfs of documents available in Reflector repository).
  12. Test262 Status Updates (15m)
    1. Features flags.
    2. Async Iteration tests.
    3. Object Rest/Spread tests.
    4. global length and name.
  13. Timeboxed overflow from previous meeting
    1. 15 Minute Items
    2. 30 Minute Items
    3. 45 Minute Items
    4. 60 Minute Items
    5. Timebox Not Yet Selected (champion, please select one)
  14. (Wednesday) Talks on Visions for the future of ECMAScript (30 min limit)
    1. Towards Trustworthy Verification of JavaScript (Philippa Gardner)
    2. Shape Security (slides) (Kevin Gibbons and Tim Disney)
    3. Follow the user (Daniel Ehrenberg; timebox: 10 minutes)
    4. Presentation by invited expert Patrick Soquet and Peter Hoddie of Moddable on ES6 in 48K of RAM (Brendan-invited, Ecma-approved)
    5. Role of Babel in JS (slides) (Henry Zhu)
    6. TC39/ECMAScript: The Next 20 Years (slides) (Allen Wirfs-Brock)
  15. Timeboxed agenda items
    1. 15 Minute Items
      1. (Thursday) RegExp Legacy Features for Stage 3 (Mark S. Miller, by Claude Pache)
      2. Math.signbit proposal (JF Bastien, presented by Keith Miller)
      3. Status update on RegExp proposals: lookbehind, Unicode properties, dotall flag and named groups status update (Daniel Ehrenberg)
      4. Intl.Segmenter for Stage 3 (spec) (Daniel Ehrenberg)
      5. Standardizing Date.prototype.toString (Daniel Ehrenberg)
      6. Float16 on TypedArrays, DataView, Math.hfround for stage 1 (Leo Balter, original request from esdiscuss) - slides.
      7. Why allow BindingPattern for BindingRestParameter for object rest. Maybe we should just allow identifiers. (Keith Miller on behalf of Saam Barati).
      8. BigInt for Stage 3 (Daniel Ehrenberg)
    2. 30 Minute Items
      1. Atomics.waitNonblocking for Stage 1 (informal explainer) (Shu-yu Guo, Lars Hansen in absentia)
      2. Module import options discussion, potentially for stage 1 (discussion; slides) (Domenic Denicola)
      3. Importing modules which failed evaluation (issue; no slides) (Domenic Denicola)
      4. Advance Numeric separators proposal to Stage 1 slides (Sam Goto)
      5. Nobody understands counterfactuals in Annex B.3.3 (Shu-yu Guo, low priority)
      6. import.meta for stage 2 (Domenic Denicola)
    3. 45 Minute Items
      1. Accessing host-specific module metadata from inside a module (issue; slides) (Domenic Denicola)
      2. Updates on class-field proposals (both public and private). (Jeff Morrison) (spec text, slides)
    4. 60 Minute Items
      1. Revisiting async generator yield behavior (issue; slides) (Domenic Denicola)
      2. Updates on Cancellation Proposals (Brian Terlson, Ron Buckton) (proposal; slides)
      3. Module/script pragma, for stage 2 (proposal; slides) (Dave Herman, Yehuda Katz)
      4. (Wednesday) BigInt towards Stage 3 (spec) (Daniel Ehrenberg)
  16. Non-timeboxed overflow from previous meeting
  17. Non-timeboxed agenda items
    1. (Thursday) Code of Conduct follow-up
    2. Web compatibility issues / Needs-consensus PRs
    3. Stage 0+ proposals looking to advance 1. Advance Observable proposal to Stage 2
    4. New proposals
    5. Discussion and updates for Stage 0+ Proposals
    6. Charing/committee leadership structure
  18. Overflow from timeboxed discussion items (in insertion order)
  19. Closure

Agenda Topic Rules

  1. Proposals looking to advance must be added to the agenda along with necessary review materials 7 days prior to the first day of the meeting.
  2. Timeboxed topics may be 15, 30, 45, or 60 minutes in length.

Schedule constraints

Dates and locations of future meetings

Dates Location Host
2017-07-25 to 2017-07-27 Redmond, WA Microsoft
2017-09-26 to 2017-09-28 Boston, MA Bocoup
2017-11-28 to 2017-11-30 San Francisco, CA Airbnb