Intl Built-ins
ECMA-402 Internationalization API reference
Implements the ECMA-402 Internationalization API . See the ECMA-402 specification for the full specification reference.
GocciaScript differences: Requires system ICU library for full functionality. Falls back to embedded CLDR data when ICU is unavailable.
Executive Summary
ECMA-402 conformance -- Implements the Internationalization API with locale-aware formatting for numbers, dates, lists, durations, and relative timeData strategy -- System ICU library as primary data source, embedded CLDR resource as fallback for single-binary portabilityLocale negotiation -- BCP 47 locale identifiers with Unicode extension keys, best-fit and lookup matching algorithmsSegmentation -- Intl.Segmenter provides Unicode-aware grapheme, word, and sentence segmentationCollation and display -- Intl.Collator for locale-sensitive string comparison, Intl.DisplayNames for localized display of language, region, and script names
Data Strategy
Intl constructors load locale data from ICU libraries or embedded CLDR data. Lookup order is:
System ICU library (preferred for full locale coverage and up-to-date data)
Embedded CLDR resource (fallback for environments without ICU)
Platform Library Notes macOS libicucoreShips with the OS; available on all supported macOS versions Linux libicui18nTypically provided by the libicu or icu system package Windows icu.dllAvailable on Windows 10 1903+ (shared with Temporal timezone support)
The embedded CLDR data is generated from upstream CLDR JSON distributions and linked as a FreePascal .res resource. This keeps locale data available in single-binary builds even when system ICU cannot provide the requested data. Define GOCCIA_INTL_NO_EMBEDDED_CLDR at compile time to omit the embedded fallback.
Namespace Structure
Intl.Locale // Unicode locale identifier
Intl.Collator // Locale-sensitive string comparison
Intl.NumberFormat // Locale-sensitive number formatting
Intl.DateTimeFormat // Locale-sensitive date and time formatting
Intl.PluralRules // Plural-sensitive formatting
Intl.RelativeTimeFormat // Locale-sensitive relative time formatting
Intl.ListFormat // Locale-sensitive list formatting
Intl.DisplayNames // Locale-sensitive display names
Intl.Segmenter // Unicode segmentation
Intl.DurationFormat // Locale-sensitive duration formatting
Static methods:
Method Description Intl.getCanonicalLocales(locales)Return an array of canonical locale strings Intl.supportedValuesOf(key)Return an array of supported values for a given key ("calendar", "collation", "currency", "numberingSystem", "timeZone", "unit")
Intl.Locale
Represents a Unicode locale identifier with parsed subtags and extension keys.
Constructor / Static Description new Intl.Locale(tag, options?)Create from a BCP 47 language tag string with optional override options
Getter Description baseNameBase locale identifier without extension keys calendarCalendar type (Unicode ca extension) caseFirstCase-first sort order ("upper", "lower", "false") collationCollation type (Unicode co extension) hourCycleHour cycle ("h11", "h12", "h23", "h24") languageLanguage subtag numberingSystemNumbering system (Unicode nu extension) numericWhether numeric collation is enabled regionRegion subtag scriptScript subtag
Method Description maximize()Return a new Locale with likely subtags added minimize()Return a new Locale with likely subtags removed getCalendars()Return an array of preferred calendars getCollations()Return an array of preferred collations getHourCycles()Return an array of preferred hour cycles getNumberingSystems()Return an array of preferred numbering systems getTimeZones()Return an array of preferred time zones getTextInfo()Return an object with direction ("ltr" or "rtl") getWeekInfo()Return an object with firstDay and weekend toString()Return the canonical locale string
Intl.Collator
Provides locale-sensitive string comparison.
Constructor / Static Description new Intl.Collator(locales?, options?)Create a collator for the given locale(s) Intl.Collator.supportedLocalesOf(locales, options?)Return supported locales from the requested list
Method Description compare(x, y)Compare two strings; returns negative, zero, or positive resolvedOptions()Return an object reflecting the locale and collation options
Provides locale-sensitive number formatting.
Constructor / Static Description new Intl.NumberFormat(locales?, options?)Create a number formatter for the given locale(s) Intl.NumberFormat.supportedLocalesOf(locales, options?)Return supported locales from the requested list
Method Description format(value)Format a number as a locale-specific string formatToParts(value)Return an array of format parts with type and value formatRange(start, end)Format a range between two numbers formatRangeToParts(start, end)Return an array of format parts for a range resolvedOptions()Return an object reflecting the locale and formatting options
Provides locale-sensitive date and time formatting.
Constructor / Static Description new Intl.DateTimeFormat(locales?, options?)Create a date/time formatter for the given locale(s) Intl.DateTimeFormat.supportedLocalesOf(locales, options?)Return supported locales from the requested list
Method Description format(date)Format a date as a locale-specific string formatToParts(date)Return an array of format parts with type and value formatRange(startDate, endDate)Format a date range formatRangeToParts(startDate, endDate)Return an array of format parts for a date range resolvedOptions()Return an object reflecting the locale and formatting options
Intl.PluralRules
Provides plural-sensitive formatting and plural category selection.
Constructor / Static Description new Intl.PluralRules(locales?, options?)Create plural rules for the given locale(s) Intl.PluralRules.supportedLocalesOf(locales, options?)Return supported locales from the requested list
Method Description select(value)Return the plural category ("zero", "one", "two", "few", "many", "other") selectRange(start, end)Return the plural category for a range resolvedOptions()Return an object reflecting the locale and plural options
Provides locale-sensitive relative time formatting.
Constructor / Static Description new Intl.RelativeTimeFormat(locales?, options?)Create a relative time formatter for the given locale(s) Intl.RelativeTimeFormat.supportedLocalesOf(locales, options?)Return supported locales from the requested list
Method Description format(value, unit)Format a relative time value (e.g., "in 3 days", "2 hours ago") formatToParts(value, unit)Return an array of format parts with type and value resolvedOptions()Return an object reflecting the locale and formatting options
Provides locale-sensitive list formatting.
Constructor / Static Description new Intl.ListFormat(locales?, options?)Create a list formatter for the given locale(s) Intl.ListFormat.supportedLocalesOf(locales, options?)Return supported locales from the requested list
Method Description format(list)Format a list of strings (e.g., "A, B, and C") formatToParts(list)Return an array of format parts with type and value resolvedOptions()Return an object reflecting the locale and formatting options
Intl.DisplayNames
Provides localized display names for languages, regions, scripts, currencies, calendars, and date-time fields.
Constructor / Static Description new Intl.DisplayNames(locales, options)Create a display name resolver for the given locale(s) and type Intl.DisplayNames.supportedLocalesOf(locales, options?)Return supported locales from the requested list
Method Description of(code)Return the display name for the given code, or undefined resolvedOptions()Return an object reflecting the locale and display name options
Intl.Segmenter
Provides Unicode-aware text segmentation by grapheme, word, or sentence boundaries.
Constructor / Static Description new Intl.Segmenter(locales?, options?)Create a segmenter for the given locale(s) and granularity Intl.Segmenter.supportedLocalesOf(locales, options?)Return supported locales from the requested list
Method Description segment(string)Return a Segments object for iterating over segments resolvedOptions()Return an object reflecting the locale and segmentation options
Segments object:
Method Description containing(index)Return the segment at the given index [Symbol.iterator]()Iterate over segments, each with segment, index, input, and isWordLike (word granularity only)
Provides locale-sensitive duration formatting.
Constructor / Static Description new Intl.DurationFormat(locales?, options?)Create a duration formatter for the given locale(s) Intl.DurationFormat.supportedLocalesOf(locales, options?)Return supported locales from the requested list
Method Description format(duration)Format a duration object as a locale-specific string formatToParts(duration)Return an array of format parts with type and value resolvedOptions()Return an object reflecting the locale and formatting options