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Ecma TC39

Ecma International, Technical Committee 39 - ECMAScript

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TC39

Ecma International's TC39 is a group of JavaScript developers, implementers, academics, and more, collaborating with the community to maintain and evolve the definition of JavaScript.

Contribute

TC39 welcomes contributions from the JavaScript community, whether it is feedback on existing proposals, improved documentation, testing, implementations, or even language feature ideas. See our contributor guide for details.

Important

To participate in TC39 meetings as a member, join Ecma.

Specifications

We develop the JavaScript (formally, ECMAScript) specification, the Internationalization API specification, the Source Map specification, and, of course, JSON! We meet every two months to discuss proposals. To learn more about the process, please take a look at the six stages for new language feature proposals. See our meeting agendas and minutes to learn more.

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  1. ecma262 ecma262 Public

    Status, process, and documents for ECMA-262

    HTML 15.5k 1.4k

  2. ecma402 ecma402 Public

    Status, process, and documents for ECMA 402

    HTML 585 113

  3. test262 test262 Public

    Official ECMAScript Conformance Test Suite

    JavaScript 2.6k 512

  4. proposals proposals Public

    Tracking ECMAScript Proposals

    19k 739

  5. agendas agendas Public

    TC39 meeting agendas

    JavaScript 1.2k 199

  6. notes notes Public

    TC39 meeting notes

    JavaScript 693 126

Repositories

Showing 10 of 310 repositories
  • proposal-temporal Public

    Provides standard objects and functions for working with dates and times.

    tc39/proposal-temporal’s past year of commit activity
    HTML 3,618 171 34 9 Updated Nov 15, 2025
  • dataset Public

    The automatic track tc39 proposals

    tc39/dataset’s past year of commit activity
    TypeScript 45 Unlicense 12 2 0 Updated Nov 15, 2025
  • ecma426 Public

    Source map specification, RFCs and new proposals.

    tc39/ecma426’s past year of commit activity
    JavaScript 172 22 62 7 Updated Nov 14, 2025
  • ecma262 Public

    Status, process, and documents for ECMA-262

    tc39/ecma262’s past year of commit activity
    HTML 15,534 1,373 353 (9 issues need help) 123 Updated Nov 14, 2025
  • test262 Public

    Official ECMAScript Conformance Test Suite

    tc39/test262’s past year of commit activity
    JavaScript 2,630 512 213 (4 issues need help) 72 Updated Nov 14, 2025
  • tc39.github.io Public

    Get involved in specifying JavaScript

    tc39/tc39.github.io’s past year of commit activity
    HTML 332 MIT 62 27 (3 issues need help) 2 Updated Nov 14, 2025
  • agendas Public

    TC39 meeting agendas

    tc39/agendas’s past year of commit activity
    JavaScript 1,164 199 0 3 Updated Nov 13, 2025
  • proposal-await-dictionary Public

    A proposal to add Promise.allKeyed to ECMAScript

    tc39/proposal-await-dictionary’s past year of commit activity
    JavaScript 96 MIT 7 7 1 Updated Nov 13, 2025
  • proposal-intl-era-monthcode Public

    To specify necessary details about era, eraYear and monthCode usage with Temporal for non-ISO calendars.

    tc39/proposal-intl-era-monthcode’s past year of commit activity
    HTML 4 MIT 8 17 3 Updated Nov 13, 2025
  • proposal-amount Public

    Numbers with precision and a unit for JavaScript

    tc39/proposal-amount’s past year of commit activity
    HTML 37 MIT 5 31 3 Updated Nov 13, 2025