tc39/proposal-temporal

Features

• Date and Time Libraries - Implements a comprehensive date and time library for managing complex calculations across time zones and calendars.
• Immutable Temporal APIs - Provides a comprehensive immutable API for performing date and time calculations across multiple calendar systems.
• Object Serializers - Provides industry-standard serialization of temporal data objects into machine-readable strings for consistent storage.
• Date Component Extractors - Provides utilities for retrieving individual date properties such as year, month, and day.
• JavaScript APIs - Proposes a new immutable date and time API for JavaScript to replace the legacy Date object.
• Temporal Component Extraction - Extracts individual units such as hour, minute, second, and nanosecond as read-only properties.
• Temporal Serialization - Supports bidirectional conversion of date and time objects to and from standardized strings like ISO 8601.
• Immutable Date Processing - Enforces a strictly immutable object model for all date and time instances to prevent side-effect mutations.
• Time Zone Management - Manages global timestamps and wall-clock time using IANA time zone resolution and daylight saving transition logic.
• Time Zone Conversions - Transforms absolute instants into local date-time components using regional time zone databases.
• Wall-Clock Conversions - Transforms global timestamps into human-readable date and time using a specific time zone and calendar.
• Zoned Date-Time Instantiations - Constructs zoned date-time objects from epoch nanoseconds or strings including time zone information.
• Calendar-Agnostic Engines - Implements a decoupled internal standard that allows date calculations to work across any supported calendar system.
• Calendar Date Representations - Creates immutable date objects containing year, month, and day based on a specific calendar.
• Cross-Calendar Tracking - Maintains a consistent internal ISO representation while allowing dates to be tracked in various calendar systems.
• Zoned Date-Time Representations - Implements a comprehensive representation of a precise moment combining date, time, time zone, and calendar.
• Multi-Calendar Conversions - Provides algorithms for transforming dates between diverse cultural calendar systems to ensure consistency.
• Multi-Calendar Engines - Serves as a multi-calendar date engine for representing and converting dates across various global calendar systems.
• Epoch-Based Time Representations - Implements high-precision time tracking relative to the Unix epoch using nanoseconds.
• Temporal Arithmetic - Adds or subtracts a duration from a date-time to calculate a future or past point with precision.
• DST-Safe Arithmetic - Adds or subtracts durations using rules that maintain consistent clock time across daylight saving.
• Cross-Calendar Comparisons - Determines the chronological order of two dates regardless of the calendar systems they use.
• Cross-Calendar Date-Time Comparisons - Determines if one date-time occurs before, after, or at the same time as another across calendars.
• Date String Serialization - Implements standardized conversion of date and time objects into machine-readable strings for consistent storage.
• Plain Date Instantiations - Enables the instantiation of plain date objects from numeric components or date strings.
• Plain Date-Time Instantiations - Provides methods to instantiate date-time objects using numeric components or standardized strings.
• Plain Time Instantiations - Supports generating time-of-day objects from individual numeric components or ISO 8601 strings.
• Duration Instantiations - Provides mechanisms to instantiate duration objects using numeric values, property bags, or ISO 8601 strings.
• Wall-Clock Time Representations - Implements immutable time objects with nanosecond precision for representing hours, minutes, and seconds.
• Precision Timing APIs - Provides a language-level API for tracking time with nanosecond precision relative to the Unix epoch.
• Time Zone Converters - Converts date and time objects across different time zones while preserving local time.
• String Parsing - Converts standardized date and time strings into structured data objects while ignoring extraneous information.
• Calendar Arithmetic - Calculates date changes using calendar-specific logic for months and years to ensure high accuracy.
• Date and Time Utilities - Provides a general-purpose library for performing precise arithmetic, finding durations, and calculating date differences.
• IANA Time Zone Database Integrations - Integrates the IANA time zone database to resolve regional offsets and historical time transitions with precision.
• Multi-Calendar Systems - Implements a core library for projecting and managing date-times across multiple distinct calendar systems.
• Temporal Interval Measurements - Calculates durations between two points in time using calendar-aware units like years and months.
• Instant Instantiations - Allows creating precise moments in time using nanosecond values or ISO 8601 strings.
• Plain Date-Time Representations - Implements an immutable representation for wall-clock dates and times without time zone information.
• Calendar System Projections - Enables projecting a date into a different calendar system while maintaining the identical calendar day.
• Date to Date-Time Conversions - Combines a date with a specific time of day to create a full date-time representation.
• Chronological Comparisons - Provides logic for comparing and ordering arrays of date-time objects and ISO 8601 strings chronologically.
• Date Component Modifiers - Modifies specific parts of a date with configurable overflow behavior to handle invalid dates immutably.
• Localized Formatting - Converts temporal objects into ISO 8601 strings or regionalized formats based on language codes.
• Temporal Comparison Operators - Provides generic logic to determine the chronological relationship between date, time, or duration objects.
• System Time Zone Identification - Retrieves the current system time zone as a named IANA identifier.
• Date to Zoned Date-Time Conversions - Merges a date with a time and a time zone to create a precise wall-clock time.
• Zone Transition Identification - Identifies the next exact moment a time zone undergoes an offset transition.
• Zoned Date-Time Comparisons - Determines if one zoned date time occurs before, after, or at the same instant as another.
• Zoned Time Projections - Projects the current instant into a target time zone to create a zoned date-time instance.
• Zoned Time Transformations - Transforms a time point into a calendar date and wall-clock time by applying a specific time zone.
• Zoned-to-Plain Projections - Allows transforming zoned date-time objects into plain calendar date-times while preserving local time.
• Transition Discovery - Locates the closest past or future UTC offset transitions for the current time zone.
• Zone Transition Handling - Identifies the next or previous time zone offset change for a specific zoned date-time.
• Zoned Duration Calculations - Computes elapsed time between zoned date-times as hybrid durations of calendar days.
• Calendar Date Manipulators - Determines specific dates based on calendar rules, such as finding the nth weekday of a month.
• Calendar-Aware Date Differences - Computes the number of years, months, or days between two dates using calendar-aware logic.
• Overflow Strategies - Handles invalid calendar date inputs using specific overflow and clamping strategies.
• Zoned Calendar Projections - Creates new zoned date-times by projecting the current instant into a different target calendar.
• Calendar Operations - Offers operations to retrieve calendar-specific metadata, including leap year status and days per month.
• Custom Calendar Extensions - Allows the implementation of custom calendar systems and astronomical ranges beyond the built-in standards.
• Month Boundary Calculations - Determines month boundaries and the number of days in a month based on the active calendar system.
• Time Offset Serialization - Converts exact time instances into strings including offsets or time zone names for data transport.
• Date-Time Field Modifications - Creates a new date-time object by overriding specific components or replacing the entire clock time.
• Temporal Rounding - Adjusts date or time objects to the nearest specified unit boundaries.
• Date and Time Combinations - Merges separate calendar date and wall-clock time values into a single combined date-time instance.
• Duration Calculations - Calculates the precise duration elapsed between two instants.
• Duration Rounding - Provides utilities to snap durations to specific increments using configurable rounding modes.
• Duration Balancing - Resolves the ambiguity of variable-length months and years using reference dates for precise duration balancing.
• Duration Comparisons - Determines if one duration is shorter, longer, or equal to another using an optional reference date.
• DST Ambiguity Resolutions - Provides mechanisms to resolve time gaps and overlaps occurring during daylight saving transitions.
• Date Comparison Utilities - Verifies if two date objects represent the same calendar date.
• Date String Formatters - Converts date objects into standardized RFC 9557 strings or language-sensitive localized formats.
• Date Localizations - Produces localized string representations of date and time data tailored to a specific locale.
• Date Difference Calculators - Computes the elapsed time between two dates as a duration with rounding and custom precision.
• Duration Arithmetic Operations - Adds or subtracts durations to produce a new balanced duration object with overflow rules.
• Clock-Wrap Arithmetic - Adds or subtracts durations to time points with automatic 24-hour clock wrapping.
• Date Duration Modifications - Adds or subtracts a specified duration of time to a date with clamping options.
• Duration Balancing - Resolves variable-length duration units using reference dates and time zone offsets.
• System Date Retrievals - Provides utilities to fetch the current date and time according to system settings and optional time zones.
• Time Interval Manipulations - Manages elapsed time intervals, including unit conversion and negation.
• UTC Offset Calculations - Calculates the UTC offset for a specific time zone at a given instant.
• Date Overflow Strategies - Includes configurable strategies to resolve invalid dates, such as clamping to the nearest valid day.
• Date-Time Equality Verifications - Verifies if two date-time objects represent the same point in time and use the same calendar.
• Month-Day to Date Conversions - Transforms a month-day object into a full calendar date by associating it with a specific year.
• System Time Retrievals - Captures the current system time with nanosecond accuracy independently of any calendar system.
• Temporal Representation Transformations - Provides capabilities to transform date and time objects between different representations, such as converting zoned date-times to plain dates.
• Wall-Clock Time Equality - Verifies if two time objects represent the exact same wall-clock time.
• Date-Time Duration Computations - Computes the elapsed time between two date-times with options for rounding and unit specification.
• ISO 8601 Standards - Provides full implementation of ISO 8601 standards for serializing complex date and time objects.
• Duration Serialization Formats - Serializes duration values into ISO 8601 strings or human-readable localized representations.
• Month-Year Types - Provides immutable representations of a specific year and month combination without a day.
• Field Overrides - Provides the ability to create new year-month objects by overriding specific fields.
• Year-Month Arithmetic - Performs addition and subtraction of months and years to calculate future year-months.
• Year-Month Interval Calculations - Computes the elapsed time between two year-months as a duration with rounding options.
• Date-Time Format Strings - Produces unambiguous RFC 9557 strings or locale-aware representations for date-time human readability.
• RFC 9557 Representations - Produces unambiguous RFC 9557 string representations of dates with configurable calendar annotations.
• Zoned Date-Time Formatting - Provides the ability to convert zoned date-time objects into localized or RFC 9557 compliant strings.
• Temporal Difference Calculations - Computes durations between date or time objects using since and until operations.
• Partial Temporal Types - Provides immutable types for partial dates, such as month-day combinations for recurring events.
• Calendar System Interoperability - Provides logical interoperability by validating and coercing date objects into specific calendar systems.
• Zoned Field Updating - Allows creating new zoned date-times by overriding specific fields while preserving the original zone.

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