Releases

Performance improvements and web assembly are not included.

Highlights

Array.prototype.findLast [{a:1, b:2},{a:1, b:3}].findLast(o => o.a === 1) // { a: 1, b: 3 } |

new properties added to Intl.Locale
- textInfo, { direction: 'rtl' }
- weekInfo, {firstDay: 6, weekend: [5, 6], minimalDays: 1}
- calendars, collations, hourCycles, numberingSystems, timeZones
  - array of preferred identifiers of those in common use
Intl.supportedValuesOf

[1,2,3,4].findLast( el => el % 2 === 0) // 4
[1,2,3,4].findLastIndex( el => el % 2 === 0) // 3

Intl.DisplayNames v2
- added: calendar, dateTimeField
- enhanced the support for the “language” type with a new languageDisplay option,
Extended timeZoneName option
- Intl.DateTimeFormat API in v9.5 now supports four new values for the timeZoneName option:
  - shortGeneric to output the name of the time zone as in a short generic non-location format, such as “PT”, “ET”, without indicating whether it is under daylight saving time.
  - longGeneric to output the name of the time zone as in a short generic non-location format, such as Pacific Time, Mountain Time, without indicating whether it is under daylight saving time.
  - shortOffset to output the name of the time zone as in the short localized GMT format, such as GMT-8.
  - longOffset to output the name of the time zone as in the long localized GMT format, such as “GMT-0800”.

class C {
  // This block will run when the class itself is evaluated
  static { console.log("C's static block"); }
}

at method is now available on Arrays, TypedArrays, and Strings. [1,2,3].at(-1) is 3
- also available on FF 90

top-level await enabled by default
Private brand checks enabled by default. Extends the in operator to also work with private field #-names

Open sourced JS-Fuzzer
Speed-ups in Number.prototype.toString
Atomics.wake renamed to Atomics.notify
Anonymous classes now have a .name property whose value is the empty string ''
The built-in Reflect object now has a Symbol.toStringTag property whose value is 'Reflect'