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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 592 114

  3. test262 test262 Public

    Official ECMAScript Conformance Test Suite

    JavaScript 2.7k 520

  4. proposals proposals Public

    Tracking ECMAScript Proposals

    19k 737

  5. agendas agendas Public

    TC39 meeting agendas

    JavaScript 1.2k 199

  6. notes notes Public

    TC39 meeting notes

    JavaScript 698 125

Repositories

Showing 10 of 317 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 3,642 171 31 20 Updated Jan 13, 2026
  • ecma402 Public

    Status, process, and documents for ECMA 402

    tc39/ecma402’s past year of commit activity
    HTML 592 114 157 11 Updated Jan 13, 2026
  • dataset Public

    The automatic track tc39 proposals

    tc39/dataset’s past year of commit activity
    TypeScript 45 Unlicense 11 2 0 Updated Jan 13, 2026
  • agendas Public

    TC39 meeting agendas

    tc39/agendas’s past year of commit activity
    JavaScript 1,166 199 0 2 Updated Jan 12, 2026
  • proposal-function-and-object-literal-element-decorators Public

    ECMAScript Decorators for Function Expressions and Declarations

    tc39/proposal-function-and-object-literal-element-decorators’s past year of commit activity
    71 MIT 0 3 0 Updated Jan 12, 2026
  • test262 Public

    Official ECMAScript Conformance Test Suite

    tc39/test262’s past year of commit activity
    JavaScript 2,660 520 206 (4 issues need help) 69 Updated Jan 12, 2026
  • proposal-joint-iteration Public

    a TC39 proposal to synchronise the advancement of multiple iterators

    tc39/proposal-joint-iteration’s past year of commit activity
    TypeScript 108 4 1 0 Updated Jan 12, 2026
  • proposals Public

    Tracking ECMAScript Proposals

    tc39/proposals’s past year of commit activity
    19,022 737 6 2 Updated Jan 11, 2026
  • tc39/proposal-import-sync’s past year of commit activity
    45 MIT 2 5 0 Updated Jan 10, 2026
  • proposal-first-class-protocols Public

    a proposal to bring protocol-based interfaces to ECMAScript users

    tc39/proposal-first-class-protocols’s past year of commit activity
    JavaScript 360 MIT 8 20 0 Updated Jan 9, 2026