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 ourcontributor guide for details.

Important

To participate in TC39 meetings as a member,join Ecma.

Specifications

We develop theJavaScript (formally, ECMAScript) specification, theInternationalization API specification, theSource 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 thesix stages for new language featureproposals. See ourmeeting agendas andminutes to learn more.

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ecma262ecma262Public
Status, process, and documents for ECMA-262
HTML 15.5k 1.4k
ecma402ecma402Public
Status, process, and documents for ECMA 402
HTML 585 113
test262test262Public
Official ECMAScript Conformance Test Suite
JavaScript 2.6k 507
proposalsproposalsPublic
Tracking ECMAScript Proposals
19k 741
agendasagendasPublic
TC39 meeting agendas
JavaScript 1.2k 199
notesnotesPublic
TC39 meeting notes
JavaScript 692 127

Showing 10 of 308 repositories

test262 Public
Official ECMAScript Conformance Test Suite
tc39/test262’s past year of commit activity
JavaScript 2,621 507 211 (4 issues need help) 69 UpdatedNov 6, 2025
agendas Public
TC39 meeting agendas
tc39/agendas’s past year of commit activity
JavaScript 1,161 199 0 4 UpdatedNov 6, 2025
proposal-temporal Public
Provides standard objects and functions for working with dates and times.
tc39/proposal-temporal’s past year of commit activity
HTML 3,615 172 34 8 UpdatedNov 6, 2025
dataset Public
The automatic track tc39 proposals
tc39/dataset’s past year of commit activity
TypeScript 45Unlicense 13 2 0 UpdatedNov 6, 2025
ecma262 Public
Status, process, and documents for ECMA-262
tc39/ecma262’s past year of commit activity
HTML 15,526 1,372 355 (9 issues need help) 120 UpdatedNov 5, 2025
tc39.github.io Public
Get involved in specifying JavaScript
tc39/tc39.github.io’s past year of commit activity
HTML 332MIT 63 27 (3 issues need help) 2 UpdatedNov 5, 2025
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 96 3 0 0 UpdatedNov 5, 2025
proposal-iterator-sequencing Public
a TC39 proposal to create iterators by sequencing existing iterators
tc39/proposal-iterator-sequencing’s past year of commit activity
JavaScript 79 4 0 0 UpdatedNov 3, 2025
ecmarkup Public
An HTML superset/Markdown subset source format for ECMAScript and related specifications
tc39/ecmarkup’s past year of commit activity
HTML 234MIT 74 97 10 UpdatedNov 3, 2025
proposal-intl-keep-trailing-zeros Public
tc39/proposal-intl-keep-trailing-zeros’s past year of commit activity
3MIT 1 2 2 UpdatedNov 1, 2025