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@tc39

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 610 120

  3. test262 test262 Public

    Official ECMAScript Conformance Test Suite

    JavaScript 2.8k 564

  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
  • tc39/proposal-deferred-reexports's past year of commit activity
    61 MIT 7 15 2 Updated Sep 21, 2026
  • proposal-defer-import-eval Public

    A proposal for introducing a way to defer evaluate of a module

    tc39/proposal-defer-import-eval's past year of commit activity
    HTML 320 MIT 23 8 1 Updated Sep 21, 2026
  • test262 Public

    Official ECMAScript Conformance Test Suite

    tc39/test262's past year of commit activity
    JavaScript 2,821 564 213 (4 issues need help) 109 Updated Sep 21, 2026
  • ecmarkup Public

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

    tc39/ecmarkup's past year of commit activity
    TypeScript 245 MIT 80 100 18 Updated Sep 21, 2026
  • dataset Public

    The automatic track tc39 proposals

    tc39/dataset's past year of commit activity
    TypeScript 50 Unlicense 14 2 0 Updated Sep 21, 2026
  • ecma262 Public

    Status, process, and documents for ECMA-262

    tc39/ecma262's past year of commit activity
    HTML 15,691 1,433 354 (8 issues need help) 122 Updated Sep 20, 2026
  • agendas Public

    TC39 meeting agendas

    tc39/agendas's past year of commit activity
    JavaScript 1,174 202 1 3 Updated Sep 19, 2026
  • proposal-intl-unit-protocol Public

    TC39 proposal for adding units to format functions

    tc39/proposal-intl-unit-protocol's past year of commit activity
    JavaScript 8 MIT 0 3 0 Updated Sep 19, 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 48 MIT 4 7 0 Updated Sep 18, 2026
  • proposal-export-star-default Public

    Proposal to include default export in `export * from 'module'`

    tc39/proposal-export-star-default's past year of commit activity
    JavaScript 13 MIT 0 3 0 Updated Sep 18, 2026