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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 740

  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
  • agendas Public

    TC39 meeting agendas

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

    ECMAScript Proposal and spec for exposing a native promise predicate

    tc39/proposal-native-promise-predicate’s past year of commit activity
    JavaScript 12 MIT 1 3 1 Updated Nov 13, 2025
  • proposal-native-promise-adoption Public

    ECMAScript Proposal for adopting native promise state

    tc39/proposal-native-promise-adoption’s past year of commit activity
    JavaScript 7 MIT 0 1 0 Updated Nov 13, 2025
  • proposals Public

    Tracking ECMAScript Proposals

    tc39/proposals’s past year of commit activity
    18,976 741 6 4 Updated Nov 13, 2025
  • dataset Public

    The automatic track tc39 proposals

    tc39/dataset’s past year of commit activity
    TypeScript 45 Unlicense 12 2 0 Updated Nov 13, 2025
  • ecmarkup Public

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

    tc39/ecmarkup’s past year of commit activity
    HTML 234 MIT 75 97 9 Updated Nov 12, 2025
  • proposal-amount Public

    Numbers with precision and a unit for JavaScript

    tc39/proposal-amount’s past year of commit activity
    HTML 36 MIT 5 31 3 Updated Nov 12, 2025
  • test262 Public

    Official ECMAScript Conformance Test Suite

    tc39/test262’s past year of commit activity
    JavaScript 2,626 512 213 (4 issues need help) 71 Updated Nov 12, 2025
  • proposal-error-stack-accessor Public

    ECMAScript Proposal, specs, and reference implementation for Error.prototype.stack accessor

    tc39/proposal-error-stack-accessor’s past year of commit activity
    19 MIT 2 5 1 Updated Nov 12, 2025