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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 15.6k 1.4k

  2. ecma402 ecma402 Public

    Status, process, and documents for ECMA 402

    HTML 600 115

  3. test262 test262 Public

    Official ECMAScript Conformance Test Suite

    JavaScript 2.7k 535

  4. proposals proposals Public

    Tracking ECMAScript Proposals

    19.1k 748

  5. agendas agendas Public

    TC39 meeting agendas

    JavaScript 1.2k 201

  6. notes notes Public

    TC39 meeting notes

    JavaScript 706 125

Repositories

Showing 10 of 324 repositories
  • ecma262 Public

    Status, process, and documents for ECMA-262

    tc39/ecma262’s past year of commit activity
  • dataset Public

    The automatic track tc39 proposals

    tc39/dataset’s past year of commit activity
    TypeScript 47 Unlicense 11 2 0 Updated Apr 9, 2026
  • ecma426 Public

    Source map specification, RFCs and new proposals.

    tc39/ecma426’s past year of commit activity
    JavaScript 185 25 63 11 Updated Apr 8, 2026
  • ecmarkup Public

    An HTML superset/Markdown subset source format for ECMAScript and related specifications

    tc39/ecmarkup’s past year of commit activity
    TypeScript 239 MIT 75 99 17 Updated Apr 8, 2026
  • tc39/proposal-deferred-reexports’s past year of commit activity
    52 MIT 5 9 3 Updated Apr 8, 2026
  • 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 97 1 0 1 Updated Apr 8, 2026
  • proposal-temporal Public

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

    tc39/proposal-temporal’s past year of commit activity
    HTML 3,684 174 17 4 Updated Apr 8, 2026
  • test262 Public

    Official ECMAScript Conformance Test Suite

    tc39/test262’s past year of commit activity
    JavaScript 2,733 535 211 (4 issues need help) 94 Updated Apr 7, 2026
  • agendas Public

    TC39 meeting agendas

    tc39/agendas’s past year of commit activity
    JavaScript 1,171 201 0 3 Updated Apr 7, 2026
  • ecma402 Public

    Status, process, and documents for ECMA 402

    tc39/ecma402’s past year of commit activity
    HTML 600 115 162 8 Updated Apr 7, 2026

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