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.

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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.

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


We develop the JavaScript (formally, ECMAScript) specification on GitHub and 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.

State of Proposals

Current Candidates for the Specification

This section features proposals that are in Stage 3 of our process, which means they are close to completion.

How to read the proposals list

Each proposal has links out to other resources. The tags identify the following attributes. Below you will find a table with example tags and their meanings. All tags have hover text if you need help getting oriented.

Types of tags and what they mean


Authors and Champions: Philipp Dunkel, Maggie Johnson-Pint, Matt Johnson-Pint, Brian Terlson, Shane Carr, Ujjwal Sharma, Philip Chimento, Jason Williams, Justin Grant
Provides standard objects and functions for working with dates and times.

Intl Locale Info

Authors and Champions: Frank Yung-Fong Tang
An API to expose information of locale, such as week data ( first day of a week, weekend start, weekend end), hour cycle, measurement system, commonly used calendar, etc.


Authors: Daniel Ehrenberg, Kristen Hewell Garrett | Champion Kristen Hewell Garrett
Decorators for ES6 classes

Import Attributes

Authors: Myles Borins, Sven Sauleau, Dan Clark, Daniel Ehrenberg | Champions: Sven Sauleau, Dan Clark, Daniel Ehrenberg, Nicolò Ribaudo
Proposal for syntax to import ES modules with assertions


Authors and Champions: Jordan Harband
ECMAScript Proposal, specs, and reference implementation for Promise.try

Dynamic Code Brand Checks

Author: Nicolo Ribaudo | Champions: Krzysztof Kotowicz, Mike Samuel, Nicolo Ribaudo
TC39 proposal that enables flexible brand checks before dynamic code loading

JSON Modules

Authors and Champions: Myles Borins, Sven Sauleau, Dan Clark, Daniel Ehrenberg
Proposal to import JSON files as modules
See proposals in all stages