Add a dayPeriod option to Intl.DateTimeFormat() method so the caller can format times such as "7 in the morning", "11 in the morning", "12 noon", "1 in the afternoon", "6 in the evening", "10 at night" (or in Chinese, "清晨7時", "上午11時", "中午12時", "下午1時" ,"下午6時" ,"晚上10時")
This enhances Intl.DateTimeFormat() to match what is already possible in C++ and Java by calling ICU and ICU4J. Without this feature, developers need to either format the quarter in the server or ship a set of day period patterns and hour to day period mappings from the server to client to perform such task.
Docs: https://tc39.es/ecma402/#table-datetimeformat-components https://tc39.es/ecma402/#sec-todatetimeoptions https://tc39.es/ecma402/#sec-intl.datetimeformat-internal-slots https://tc39.es/ecma402/#table-datetimeformat-rangepatternfields https://github.com/tc39/ecma402/pull/346
Samples: https://github.com/tc39/ecma402/pull/346
Explainers: https://docs.google.com/document/d/10l10gpw5hBdZ1OuYVqZPU72-61yyOaTUQllIVRyQoFM/edit#