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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 15.7k 1.4k

  2. ecma402 ecma402 Public

    Status, process, and documents for ECMA 402

    HTML 609 120

  3. test262 test262 Public

    Official ECMAScript Conformance Test Suite

    JavaScript 2.8k 567

  4. proposals proposals Public

    Tracking ECMAScript Proposals

    19.2k 749

  5. agendas agendas Public

    TC39 meeting agendas

    JavaScript 1.2k 202

  6. notes notes Public

    TC39 meeting notes

    JavaScript 715 131

Repositories

Showing 10 of 337 repositories
  • proposal-intl-sequence-units Public

    Support for CLDR mixed units, like "5ft 6in"

    tc39/proposal-intl-sequence-units's past year of commit activity
    JavaScript 1 MIT 1 8 2 Updated Sep 29, 2026
  • agendas Public

    TC39 meeting agendas

    tc39/agendas's past year of commit activity
    JavaScript 1,176 202 1 3 Updated Sep 29, 2026
  • proposal-intl-unit-protocol Public

    TC39 proposal for adding units to format functions

    tc39/proposal-intl-unit-protocol's past year of commit activity
    JavaScript 8 MIT 0 3 0 Updated Sep 29, 2026
  • dataset Public

    The automatic track tc39 proposals

    tc39/dataset's past year of commit activity
    TypeScript 50 Unlicense 14 2 0 Updated Sep 29, 2026
  • tc39/proposal-deferred-reexports's past year of commit activity
    61 MIT 7 6 2 Updated Sep 28, 2026
  • ecma426 Public

    Source map specification, RFCs and new proposals.

    tc39/ecma426's past year of commit activity
    JavaScript 188 31 73 8 Updated Sep 28, 2026
  • tc39/source-map-tests's past year of commit activity
    JavaScript 12 11 8 0 Updated Sep 28, 2026
  • proposal-amount Public

    Numbers with precision and a unit for JavaScript

    tc39/proposal-amount's past year of commit activity
    HTML 60 MIT 12 46 8 Updated Sep 28, 2026
  • data Public

    TC39's source of truth for programmatically available process/proposal data.

    tc39/data's past year of commit activity
    JavaScript 1 MIT 0 1 1 Updated Sep 28, 2026
  • proposals Public

    Tracking ECMAScript Proposals

    tc39/proposals's past year of commit activity
    19,196 749 4 5 Updated Sep 28, 2026