Explicit fields · explicit locales · explicit support state

Intl.DurationFormat lab

Formatting begins after time semantics. This lab does not measure elapsed time, compare instants, balance or round units, schedule across DST, express relative time, or run a countdown.

Duration record

Display contract

Per-unit overrides

Leave a control on “inherit” to use the base style or display policy. Numeric widths are offered only for hour, minute, and second fields.

Rendered label

Ready.

Run the formatter.

Parts in emitted order

Native formatToParts output; the unsupported fallback has no localized parts
IndexTypeValueUnit

State contract

Nativelocalized output, emitted parts, requested and resolved locale/options
Unsupportedclearly labeled unlocalized numeric fields plus machine-readable JSON; not a polyfill
Invalidreject before constructing Intl.DurationFormat
Naive Englishcomparison-only defect demo; never used as production fallback

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