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 511
proposalsproposalsPublic
Tracking ECMAScript Proposals
19k 741
agendasagendasPublic
TC39 meeting agendas
JavaScript 1.2k 199
notesnotesPublic
TC39 meeting notes
JavaScript 693 126

Showing 10 of 310 repositories

test262 Public
Official ECMAScript Conformance Test Suite
tc39/test262’s past year of commit activity
JavaScript 2,625 511 213 (4 issues need help) 69 UpdatedNov 12, 2025
proposal-error-stack-accessor Public
ECMAScript Proposal, specs, and reference implementation for Error.prototype.stack accessor
tc39/proposal-error-stack-accessor’s past year of commit activity
19MIT 2 5 1 UpdatedNov 12, 2025
agendas Public
TC39 meeting agendas
tc39/agendas’s past year of commit activity
JavaScript 1,163 199 0 4 UpdatedNov 12, 2025
dataset Public
The automatic track tc39 proposals
tc39/dataset’s past year of commit activity
TypeScript 45Unlicense 12 2 0 UpdatedNov 12, 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 3,616 171 36 8 UpdatedNov 11, 2025
proposal-async-context Public
Async Context for JavaScript
tc39/proposal-async-context’s past year of commit activity
HTML 782CC0-1.0 24 22 5 UpdatedNov 11, 2025
proposal-native-promise-adoption Public
ECMAScript Proposal for adopting native promise state
tc39/proposal-native-promise-adoption’s past year of commit activity
JavaScript 7MIT0 1 0 UpdatedNov 11, 2025
proposal-native-promise-predicate Public
ECMAScript Proposal and spec for exposing a native promise predicate
tc39/proposal-native-promise-predicate’s past year of commit activity
JavaScript 11MIT 1 3 1 UpdatedNov 11, 2025
proposal-intl-era-monthcode Public
To specify necessary details about era, eraYear and monthCode usage with Temporal for non-ISO calendars.
tc39/proposal-intl-era-monthcode’s past year of commit activity
HTML 4MIT 8 18 4 UpdatedNov 11, 2025
proposal-Declarations-in-Conditionals Public
tc39/proposal-Declarations-in-Conditionals’s past year of commit activity
JavaScript 125 4 6 0 UpdatedNov 11, 2025