Atomics.wait, Atomics.notify, Atomics.waitAsync 24 September 2020 ECMAScript ES2020Nullish coalescing 17 September 2019 ECMAScript ES2020Optional chaining 27 August 2019 ECMAScript ES2020globalThis 16 July 2019 ECMAScript ES2020Promise combinators 12 June 2019 ECMAScript ES2020 ES2021String.prototype.matchAll 02 February 2019 ECMAScript ES2020Module namespace exports 18 December 2018 ECMAScript ES