quantify 0.12.0

A type-safe unit of measurement converter library for Dart with elegant syntax, high precision, and optimal performance.

Changelog

All notable changes to the quantify package will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

0.12.0

Added

• Major Feature: Comprehensive Constants Library.
  • A library of over 100 type-safe constants, organized into three categories: PhysicalConstants, AstronomicalConstants, and EngineeringConstants.
  • Constants are represented as Quantity objects wherever possible (e.g., PhysicalConstants.speedOfLight is a Speed object, AstronomicalConstants.standardGravity is an Acceleration object).
  • Added convenience methods for common scientific and engineering formulas, such as PhysicalConstants.photonEnergy(), AstronomicalConstants.escapeVelocity(), and EngineeringConstants.mechanicalStress().
  • Constants are accessible via a new, separate import: package:quantify/constants.dart.

0.11.0

2025-07-27

Changed

• Conceptual Refinement of Frequency and AngularVelocity:
  • Frequency is now the comprehensive quantity for all periodic units (inverse time, T⁻¹), including rotational rates.
  • AngularVelocity remains a distinct, specialized type for rotational mechanics to ensure semantic type safety.

Added

• Frequency Unit Expansion: Added rad/s (radian per second) and deg/s (degree per second) to Frequency.
• Interoperability Between Frequency and AngularVelocity:
  • Added a safe .asFrequency getter to AngularVelocity for direct conversion to a Frequency object.
  • Added a guarded .asAngularVelocity getter to Frequency that only converts compatible rotational units (rpm, rad/s, Hz, etc.) and throws an UnsupportedError for non-rotational units (like bpm or MHz), preventing logical errors in calculations.

0.10.0

2025-07-26

• New Quantities: Energy and Power

  • Added the Energy quantity with common units (J, kJ, MJ, kWh, kcal, eV, Btu).
  • Added the Power quantity with a comprehensive set of SI, engineering, and CGS units (W, kW, MW, GW, hp, PS, Btu/h, erg/s).

• Expanded Unit Coverage

  • Added new units to Acceleration (cm/s²), Force (gf, pdl), and ElectricCharge (mAh, statC, abC)

0.9.0

2025-07-22

• Added relational operators (>, <, >=, <=) for all quantities. Comparisons are now more readable (e.g., 1.m > 99.cm).
• Added isEquivalentTo() method for explicit magnitude equality checks (e.g., 1.m.isEquivalentTo(100.cm)).

0.8.0

2025-07-22

• New Derived Quantities
  • Frequency with units (Hz, MHz, GHz, THz, rpm, etc.).
  • ElectricCharge with units (C, Ah, e, µC, etc.).
  • SolidAngle with units (sr, deg², sp).

0.7.0

2025-07-16

• New Derived Quantity
  • Area with units (m², km², ha, acre, yd², ft², etc.).
  • Volume with comprehensive SI, US customary, and cooking units (m³, L, gal, fl-oz, tsp, etc.).

0.6.0

2025-07-05

• New Derived Quantities
  • Speed: Added m/s, km/h, mph, kn, ft/s.
  • Acceleration: Added m/s², g (standard gravity), km/h/s.
  • Force: Added N (Newton), lbf, dyn, kgf, kN.

0.5.0

2025-06-29

Added

• Expanded Unit Coverage:

  • Length: Added Mm (megametre) and Gm (gigametre).
  • Mass: Added Mg (megagram) and Gg (gigagram).
  • Time: Added full range of SI prefixes (Gs to cs) and calendar units (fortnight, decade, century).
  • ElectricCurrent: Added CGS units statA (statampere) and abA (abampere/biot).

• Granular Exports: Added separate library entry points (e.g., package:quantify/length.dart) to allow for explicit imports and prevent namespace conflicts.

0.4.0

2025-06-23

Added

• New Quantity: Angle

  • Angle quantity
  • AngleUnit:
    • radian (rad): The SI-derived unit, used as the base for conversions.
    • degree (°): The most common unit for angles.
    • gradian (grad): Unit used in surveying (400 grad in a circle).
    • revolution (rev): Represents a full circle or turn.
    • arcminute ('): High-precision unit (1/60 of a degree).
    • arcsecond ("): High-precision unit (1/60 of an arcminute).
    • milliradian (mrad): Common in optics and ballistics.
  • Standard arithmetic operators (+, -, *, /) for Angle.

• New Quantity: AngularVelocity

  • AngularVelocity quantity - represents rotational speed.
  • AngularVelocityUnit:
    • radianPerSecond (rad/s): The SI-derived unit.
    • degreePerSecond (°/s).
    • revolutionPerMinute (rpm): A widely used unit for rotational speed.
    • revolutionPerSecond (rps).
  • Standard arithmetic operators for AngularVelocity.

0.3.0

2025-06-21

Added

• Expanded Unit Coverage:
  • Length:
    • SI Prefixes: hm (hectometer), dam (decameter), dm (decimeter), μm (micrometer), nm (nanometer), pm (picometer), fm (femtometer).
    • Astronomical: AU (astronomical unit), ly (light year), pc (parsec).
    • Special: Å (ångström).
  • Mass:
    • SI Prefixes: hg (hectogram), dag (decagram), dg (decigram), cg (centigram), μg (microgram), ng (nanogram).
    • Imperial/US: short ton, long ton.
    • Special: u (atomic mass unit), ct (carat).
  • Time:
    • SI Prefixes: μs (microsecond), ns (nanosecond), ps (picosecond).
    • Calendar: wk (week), mo (month), yr (year).
  • Temperature:
    • Absolute Scale: °R (rankine).

0.2.0

2025-06-16

Added

• New SI Base Quantity Types (completing all 7 SI base units):
  • Mass:
    • Mass class and MassUnit enum (kg, g, mg, t (tonne), lb, oz, st (stone), slug).
  • Amount of Substance (Molar Amount):
    • MolarAmount class and MolarUnit enum (mol, mmol, µmol, nmol, pmol, kmol).
  • Electric Current:
    • Current class and CurrentUnit enum (A, mA, µA, nA, kA).
  • Luminous Intensity:
    • LuminousIntensity class and LuminousIntensityUnit enum (cd, mcd, kcd).

0.1.0

2025-06-12

Added

• Initial Release of quantify v0.1.0
• Core Functionality:
  • Type-safe Quantity base class for representing physical quantities with a value and a unit.
  • Unit interface for defining conversion factors and symbols.
  • Immutable Quantity objects.
  • double precision for quantity values.
  • Elegant API with extension methods on num for quantity creation (e.g., 10.m, 20.celsius).
  • Extension methods on Quantity for easy value retrieval in target units (e.g., length.inKm) and for obtaining new Quantity objects in target units (e.g., length.asKm).
  • Configurable toString() method on Quantity objects supporting:
    • Conversion to a targetUnit before formatting.
    • Fixed fractionDigits.
    • Option to showUnitSymbol.
    • Custom unitSymbolSeparator.
    • Locale-aware number formatting via locale parameter (using intl package).
    • Full control over number formatting via numberFormat parameter (using intl package).
  • Arithmetic operations (+, -, * by scalar, / by scalar) for most quantities.
  • Specialized arithmetic for Temperature (difference T - T returns double, ratio T / T returns double).
  • Comparable interface implementation for sorting quantities by magnitude.
  • == operator override for value and unit equality.
• Supported Quantity Types (with units and extensions):
  • Length: Meter (m), Kilometer (km), Centimeter (cm), Millimeter (mm), Inch (in), Foot (ft), Yard (yd), Mile (mi), Nautical Mile (nmi).
  • Time: Second (s), Millisecond (ms), Minute (min), Hour (h), Day (d).
  • Temperature: Kelvin (K), Celsius (°C), Fahrenheit (°F). Handles affine conversions correctly.
  • Pressure: Pascal (Pa), Atmosphere (atm), Bar (bar), PSI (psi), Torr, mmHg, inHg, kPa, hPa, mbar, cmH₂O, inH₂O.