fractionalSecondDigits option for Intl.DateTimeFormat

Category: JavaScript
Type: New or changed feature
Status: Enabled by default (Chrome 84)
Intent stage: Prepare to ship

Breaking change: No
Enterprise impact: None
Spec maturity: Incubation
Web Platform Tests: Yes

WPT details: Tests are added to test262 ./test/intl402/DateTimeFormat/constructor-options-fractionalSecondDigits-invalid.js ./test/intl402/DateTimeFormat/constructor-options-throwing-getters-fractionalSecondDigits.js ./test/intl402/DateTimeFormat/taint-Object-prototype-fractionalSecondDigits.js ./test/intl402/DateTimeFormat/constructor-options-order-fractionalSecondDigits.js ./test/intl402/DateTimeFormat/constructor-options-fractionalSecondDigits-valid.js ./test/intl402/DateTimeFormat/prototype/formatRangeToParts/fractionalSecondDigits.js ./test/intl402/DateTimeFormat/prototype/resolvedOptions/order-fractionalSecondDigits.js ./test/intl402/DateTimeFormat/prototype/format/fractionalSecondDigits.js ./test/intl402/DateTimeFormat/prototype/formatRange/fractionalSecondDigits.js ./test/intl402/DateTimeFormat/prototype/formatToParts/fractionalSecondDigits.js

Summary

Enhances the Intl.DateTimeFormat API by adding a “ fractionalSecondDigits” option to control the format of fractions of a second.

Motivation

The Date object in ECMAScript stores time information with millisecond precision. Some web developers need to output milliseconds. This option enhances Intl.DateTimeFormat to control formatting of fractions of second. The value of millisecondDigits should be an integer between 0 to 3 to represent how many digits the DateTimeFormat should output after the decimal mark.

Standards & signals

Specification: https://github.com/tc39/ecma402/pull/347
Firefox: Positive
Safari: No signal
Web developers: No signals
Tracking bug: https://bugs.chromium.org/p/v8/issues/detail?id=9284

Ecosystem

Web Platform Tests: https://wpt.fyi/results/?q=fractionalseconddigits-option-for-intl-datetimeformat
Chrome Platform Showcase: https://chrome-platform-showcase.paulkinlan-ea.deno.net/features
GenDN reference: https://gendn.paulkinlan-ea.deno.net/features
chrome.dev demos search: https://www.google.com/search?q=site%3Achrome.dev+fractionalSecondDigits%20option%20for%20Intl.DateTimeFormat
MDN Web Docs: https://developer.mozilla.org/en-US/search?q=fractionalSecondDigits%20option%20for%20Intl.DateTimeFormat
Baseline status: https://webstatus.dev/?q=fractionalSecondDigits%20option%20for%20Intl.DateTimeFormat

Docs: https://docs.google.com/document/d/1KXbFOzTsfIHXhk0uw8p8WXIHZ1Bm1xMZXahtDOiK40Q/edit#

Samples: https://docs.google.com/document/d/1KXbFOzTsfIHXhk0uw8p8WXIHZ1Bm1xMZXahtDOiK40Q/edit#

Explainers: https://docs.google.com/document/d/1KXbFOzTsfIHXhk0uw8p8WXIHZ1Bm1xMZXahtDOiK40Q/edit#

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