Ecma TC39

Ecma International, Technical Committee 39 - ECMAScript

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Overview
Repositories
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README.md

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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ecma262 ecma262 Public

Status, process, and documents for ECMA-262

HTML 15.7k 1.4k
ecma402 ecma402 Public

Status, process, and documents for ECMA 402

HTML 607 121
test262 test262 Public

Official ECMAScript Conformance Test Suite

JavaScript 2.8k 554
proposals proposals Public

Tracking ECMAScript Proposals

19.2k 749
agendas agendas Public

TC39 meeting agendas

JavaScript 1.2k 201
notes notes Public

TC39 meeting notes

JavaScript 714 130

Repositories

Type Language Sort

proposal-amount Public
Numbers with precision and a unit for JavaScript

tc39/proposal-amount's past year of commit activity

HTML 55 MIT 12 49 2 Updated Aug 19, 2026
proposal-deferred-reexports Public

tc39/proposal-deferred-reexports's past year of commit activity

57 MIT 6 10 1 Updated Aug 19, 2026
proposal-intl-keep-trailing-zeros Public

tc39/proposal-intl-keep-trailing-zeros's past year of commit activity

JavaScript 4 MIT 3 1 0 Updated Aug 18, 2026
dataset Public
The automatic track tc39 proposals

tc39/dataset's past year of commit activity

TypeScript 48 Unlicense 12 2 0 Updated Aug 19, 2026
ecmarkup Public
An HTML superset/Markdown subset source format for ECMAScript and related specifications

tc39/ecmarkup's past year of commit activity

TypeScript 242 MIT 77 100 18 Updated Aug 18, 2026
proposal-composites Public

tc39/proposal-composites's past year of commit activity

TypeScript 284 MIT 8 26 0 Updated Aug 18, 2026
tc39.github.io Public
Get involved in specifying JavaScript

tc39/tc39.github.io's past year of commit activity

HTML 335 MIT 62 27 (2 issues need help) 5 Updated Aug 17, 2026
ecma402 Public
Status, process, and documents for ECMA 402

tc39/ecma402's past year of commit activity

HTML 607 121 168 15 Updated Aug 17, 2026
ecma262 Public
Status, process, and documents for ECMA-262

tc39/ecma262's past year of commit activity

HTML 15,674 1,425 356 (8 issues need help) 129 Updated Aug 16, 2026
speccy Public
Speccy - ECMAScript spec character picker

tc39/speccy's past year of commit activity

TypeScript 0 MIT 0 0 0 Updated Aug 15, 2026