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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 563

  4. proposals proposals Public

    Tracking ECMAScript Proposals

    19.2k 751

  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
  • dataset Public

    The automatic track tc39 proposals

    tc39/dataset's past year of commit activity
    TypeScript 50 Unlicense 14 2 0 Updated Sep 17, 2026
  • agendas Public

    TC39 meeting agendas

    tc39/agendas's past year of commit activity
    JavaScript 1,172 202 1 3 Updated Sep 16, 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 0 0 Updated Sep 16, 2026
  • tc39.github.io Public

    Get involved in specifying JavaScript

    tc39/tc39.github.io's past year of commit activity
    HTML 336 MIT 63 27 (2 issues need help) 5 Updated Sep 16, 2026
  • proposal-json-parseimmutable Public

    JSON.parseImmutable for creating Records and Tuples from JSON strings

    tc39/proposal-json-parseimmutable's past year of commit activity
    HTML 47 MIT 3 7 0 Updated Sep 16, 2026
  • proposals Public

    Tracking ECMAScript Proposals

    tc39/proposals's past year of commit activity
    19,184 752 4 4 Updated Sep 15, 2026
  • proposal-private-declarations Public

    A proposal to allow trusted code _outside_ of the class lexical scope to access private state

    tc39/proposal-private-declarations's past year of commit activity
    HTML 26 MIT 2 12 0 Updated Sep 15, 2026
  • test262 Public

    Official ECMAScript Conformance Test Suite

    tc39/test262's past year of commit activity
    JavaScript 2,821 563 213 (4 issues need help) 110 Updated Sep 15, 2026
  • ecma402 Public

    Status, process, and documents for ECMA 402

    tc39/ecma402's past year of commit activity
    HTML 609 120 170 18 Updated Sep 15, 2026
  • proposal-amount Public

    Numbers with precision and a unit for JavaScript

    tc39/proposal-amount's past year of commit activity
    HTML 58 MIT 12 46 3 Updated Sep 15, 2026