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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 579 112

  3. test262 test262 Public

    Official ECMAScript Conformance Test Suite

    JavaScript 2.6k 503

  4. proposals proposals Public

    Tracking ECMAScript Proposals

    18.9k 737

  5. agendas agendas Public

    TC39 meeting agendas

    JavaScript 1.2k 199

  6. notes notes Public

    TC39 meeting notes

    JavaScript 687 126

Repositories

Showing 10 of 307 repositories
  • ecma262 Public

    Status, process, and documents for ECMA-262

    tc39/ecma262’s past year of commit activity
    HTML 15,477 1,364 354 (10 issues need help) 122 Updated Sep 30, 2025
  • dataset Public

    The automatic track tc39 proposals

    tc39/dataset’s past year of commit activity
    TypeScript 46 Unlicense 13 2 0 Updated Sep 30, 2025
  • tc39/proposal-composites’s past year of commit activity
    TypeScript 216 MIT 5 19 0 Updated Sep 29, 2025
  • proposal-iterator-chunking Public

    a proposal to add a method to iterators for producing an iterator of its subsequences

    tc39/proposal-iterator-chunking’s past year of commit activity
    JavaScript 75 1 1 0 Updated Sep 29, 2025
  • proposal-temporal Public

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

    tc39/proposal-temporal’s past year of commit activity
    HTML 3,598 172 33 6 Updated Sep 27, 2025
  • ecma426 Public

    Source map specification, RFCs and new proposals.

    tc39/ecma426’s past year of commit activity
    JavaScript 165 22 62 5 Updated Sep 26, 2025
  • test262 Public

    Official ECMAScript Conformance Test Suite

    tc39/test262’s past year of commit activity
    JavaScript 2,599 503 209 (4 issues need help) 61 Updated Sep 25, 2025
  • how-we-work Public

    Documentation of how TC39 operates and how to participate

    tc39/how-we-work’s past year of commit activity
    212 28 21 10 Updated Sep 25, 2025
  • tc39.github.io Public

    Get involved in specifying JavaScript

    tc39/tc39.github.io’s past year of commit activity
    HTML 332 MIT 64 27 (3 issues need help) 1 Updated Sep 25, 2025
  • agendas Public

    TC39 meeting agendas

    tc39/agendas’s past year of commit activity
    JavaScript 1,153 199 0 3 Updated Sep 24, 2025