Finished Proposals

Finished proposals are proposals that have reached stage 4, and are included in the latest draft of the specification.

Proposal	Author	Champion(s)	TC39 meeting notes	Expected Publication Year
Uint8Array to/from Base64	Kevin Gibbons	Kevin Gibbons	July 2025	2026
`Math.sumPrecise`	Kevin Gibbons	Kevin Gibbons	July 2025	2026
`Error.isError`	Jordan Harband	Jordan Harband	May 2025	2026
`RegExp.escape`	Domenic Denicola Benjamin Gruenbaum Jordan Harband	Jordan Harband Kevin Gibbons	February 2025	2025
Float16 on TypedArrays, DataView, `Math.f16round`	Leo Balter	Leo Balter Kevin Gibbons	February 2025	2025
`Promise.try`	Jordan Harband	Jordan Harband	October 2024	2025
Sync Iterator helpers	Gus Caplan	Michael Ficarra Jonathan Keslin Kevin Gibbons	October 2024	2025
JSON Modules	Myles Borins Sven Sauleau Dan Clark Daniel Ehrenberg	Myles Borins Sven Sauleau Dan Clark Daniel Ehrenberg	October 2024	2025
Import Attributes	Myles Borins Sven Sauleau Dan Clark Daniel Ehrenberg	Sven Sauleau Dan Clark Daniel Ehrenberg Nicolò Ribaudo	October 2024	2025
RegExp Modifiers	Ron Buckton	Ron Buckton	October 2024	2025
New Set methods	Michał Wadas Sathya Gunasekaran Kevin Gibbons	Kevin Gibbons	April 2024	2025
Duplicate named capture groups	Kevin Gibbons	Kevin Gibbons	April 2024	2025
ArrayBuffer transfer	Shu-yu Guo Jordan Harband Yagiz Nizipli	Shu-yu Guo Jordan Harband Yagiz Nizipli	February 2024	2024
`Promise.withResolvers`	Peter Klecha	Peter Klecha	_{- 2023-11 - 2023-07 - 2023-05 - 2023-03}	2024
Array Grouping	Justin Ridgewell	Justin Ridgewell Jordan Harband	November 2023	2024
Resizable and growable ArrayBuffers	Shu-yu Guo	Shu-yu Guo	September 2023	2024
RegExp v flag with set notation + properties of strings	Markus Scherer Mathias Bynens	Mathias Bynens	May 2023	2024
`Atomics.waitAsync`	Lars Hansen	Shu-yu Guo Lars Hansen	May 2023	2024
Well-Formed Unicode Strings	Guy Bedford Bradley Farias	Guy Bedford Bradley Farias Michael Ficarra	May 2023	2024
Change Array by Copy	Ashley Claymore Robin Ricard	Ashley Claymore Robin Ricard	March 2022	2023
Symbols as WeakMap keys	Daniel Ehrenberg Richard Button Robin Ricard Leo Balter Rick Waldron Caridy Patiño	Daniel Ehrenberg Richard Button Robin Ricard Leo Balter Rick Waldron Caridy Patiño	January 2023	2023
Hashbang Grammar	Bradley Farias	Bradley Farias	July 2022	2023
Array find from last	Wenlu Wang	Wenlu Wang Daniel Rosenwasser	June 2022	2023
Error Cause	Chengzhong Wu	Chengzhong Wu Hemanth HM	October 2021	2022
Class Static Block	Ron Buckton	Ron Buckton	August 2021	2022
Accessible `Object.prototype.hasOwnProperty`	Jamie Kyle	Tierney Cyren Jamie Kyle	August 2021	2022
`.at()`	Shu-yu Guo Tab Atkins	Shu-yu Guo Tab Atkins	August 2021	2022
Ergonomic brand checks for Private Fields	Jordan Harband	Jordan Harband	July 2021	2022
Top-level `await`	Myles Borins Yulia Startsev Daniel Ehrenberg Guy Bedford Ms2ger	Myles Borins Yulia Startsev	May 2021	2022
RegExp Match Indices	Ron Buckton	Ron Buckton	May 2021	2022
Class Fields (Private instance methods and accessors, Class Public Instance Fields & Private Instance Fields, Static class fields and private static methods)	Daniel Ehrenberg	Daniel Ehrenberg Kevin Gibbons	April 2021	2022
Numeric separators	Sam Goto Rick Waldron	Sam Goto Rick Waldron Leo Balter	July 2020	2021
Logical Assignment Operators	Justin Ridgewell	Justin Ridgewell Hemanth HM	July 2020	2021
WeakRefs	Dean Tribble Sathya Gunasekaran	Dean Tribble Mark Miller Till Schneidereit Sathya Gunasekaran Daniel Ehrenberg	July 2020	2021
`Promise.any`	Mathias Bynens Kevin Gibbons Sergey Rubanov	Mathias Bynens	July 2020	2021
`String.prototype.replaceAll`	Peter Marshall Jakob Gruber Mathias Bynens	Mathias Bynens	June 2020	2021
`import.meta`	Domenic Denicola	Gus Caplan	March 2020	2020
Nullish coalescing Operator	Gabriel Isenberg	Gabriel Isenberg Justin Ridgewell Daniel Rosenwasser	December 2019	2020
Optional Chaining	Gabriel Isenberg Claude Pache Dustin Savery	Gabriel Isenberg Dustin Savery Justin Ridgewell Daniel Rosenwasser	December 2019	2020
`for-in` mechanics	Kevin Gibbons	Kevin Gibbons	December 2019	2020
`globalThis`	Jordan Harband	Jordan Harband	October 2019	2020
`Promise.allSettled`	Jason Williams Robert Pamely Mathias Bynens	Mathias Bynens	July 2019	2020
`BigInt`	Daniel Ehrenberg	Daniel Ehrenberg	June 2019	2020
`import()`	Domenic Denicola	Domenic Denicola	June 2019	2020
`String.prototype.matchAll`	Jordan Harband	Jordan Harband	March 2019	2020
`Array.prototype.{flat,flatMap}`	Brian Terlson Michael Ficarra Mathias Bynens	Brian Terlson Michael Ficarra	January 2019	2019
`String.prototype.{trimStart,trimEnd}`	Sebastian Markbåge	Sebastian Markbåge Mathias Bynens	January 2019	2019
Well-formed `JSON.stringify`	Richard Gibson	Mathias Bynens	January 2019	2019
`Object.fromEntries`	Darien Maillet Valentine	Jordan Harband Kevin Gibbons	January 2019	2019
`Function.prototype.toString` revision	Michael Ficarra	Michael Ficarra	November 2018	2019
`Symbol.prototype.description`	Michael Ficarra	Michael Ficarra	November 2018	2019
JSON superset	Richard Gibson	Mark Miller Mathias Bynens	May 2018	2019
Optional `catch` binding	Michael Ficarra	Michael Ficarra	May 2018	2019
Asynchronous Iteration	Domenic Denicola	Domenic Denicola	January 2018	2018
`Promise.prototype.finally`	Jordan Harband	Jordan Harband	January 2018	2018
RegExp Unicode Property Escapes	Mathias Bynens	Brian Terlson Daniel Ehrenberg Mathias Bynens	January 2018	2018
RegExp Lookbehind Assertions	Gorkem Yakin Nozomu Katō Daniel Ehrenberg	Daniel Ehrenberg Mathias Bynens	January 2018	2018
Rest/Spread Properties	Sebastian Markbåge	Sebastian Markbåge	January 2018	2018
RegExp named capture groups	Gorkem Yakin Daniel Ehrenberg	Daniel Ehrenberg Brian Terlson Mathias Bynens	November 2017	2018
`s` (`dotAll`) flag for regular expressions	Mathias Bynens	Brian Terlson Mathias Bynens	November 2017	2018
Lifting template literal restriction	Tim Disney	Tim Disney	March 2017	2018
Shared memory and atomics	Lars T Hansen	Lars T Hansen	January 2017	2017
Async functions	Brian Terlson	Brian Terlson	July 2016	2017
Trailing commas in function parameter lists and calls	Jeff Morrison	Jeff Morrison	July 2016	2017
`Object.getOwnPropertyDescriptors`	Jordan Harband Andrea Giammarchi	Jordan Harband Andrea Giammarchi	May 2016	2017
String padding	Jordan Harband	Jordan Harband Rick Waldron	May 2016	2017
`Object.values`/`Object.entries`	Jordan Harband	Jordan Harband	March 2016	2017
Exponentiation operator	Rick Waldron	Rick Waldron	January 2016	2016
`Array.prototype.includes`	Domenic Denicola	Domenic Denicola Rick Waldron	November 2015	2016

See also the active proposals, stage 1 proposals, stage 0 proposals, and inactive proposals documents.

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