curo 3.0.2

Powerful, modern Dart library for precise instalment credit calculations - from simple loans to advanced amortisation schedules.

Changelog

All notable changes to this project will be documented in this file.

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

3.0.2 - 2026-01-26

Fixed

• Added missing tolerance argument to solve method signatures
• Added missing changelog entry to doc/site changelog summary

3.0.1 - 2026-01-22

Fixed

• Corrected first draw-down date detection when solving for an unknown advance amount (previously skipped due to placeholder 0.0 value).
• Improved discount factor operand logging: now correctly labels time fraction as t (e.g., "t = 31/360 = 0.08611111") instead of f for Standard formula, aligning notation with US Appendix J convention.

Changed

• Removed redundant isCharge field from CashFlow record (superseded by CashFlowType.type); updated all references accordingly.

3.0.0 - 2026-01-20

Breaking Changes & Complete Rewrite

• Modern ground-up rewrite of the entire package, aligning design, behaviour, and accuracy with the sister project curo-python.
• Adopted modern Dart conventions: null-safety, sealed classes, records, enhanced enums, and idiomatic patterns.
• Flattened API structure: replaced deep OOP inheritance with a cleaner, more Pythonic composition style while retaining full type-safety.
• Redesigned core types:
  • Introduced immutable Series hierarchy (SeriesAdvance, SeriesPayment, SeriesCharge) for defining cash flow series.
  • Replaced mutable cash flow objects with lightweight immutable CashFlow records.
  • Extracted internal helpers for better testability.
• Asynchronous solving: solveRate and solveValue now return Future<double> (consistent with modern Dart expectations and the original 1.1.0 behaviour).
• Simplified precision handling: single precision parameter on Calculator (0–4 decimal places).
• All public APIs updated — existing code from ≤2.x will require migration.

Added

• Built-in pretty-printed amortisation and APR proof schedules via ScheduleRow.prettyPrint.
• Comprehensive day count convention coverage unchanged but now with cleaner implementation and better documentation.
• Greatly expanded internal test coverage.

Removed

• Legacy mutable cash flow classes and deep inheritance chains.
• Old synchronous solve methods.

This major version represents a transformative modernisation while preserving (and in many cases improving) numerical accuracy and regulatory compliance.

2.4.3 - 2025-12-14

Enhancements

• Enhanced same-date CashFlowAdvance sorting by amount descending (most negative first).

Fixed

• Corrected priority of same-date advances in profile sorting.

2.4.2 - 2025-12-12

Enhancements

• Improved cash flow sorting to consistently order same-date flows: advances → payments → charges.
• Added ==, hashCode, and copyWith to DayCountFactor.

2.4.1 - 2025-12-08

Enhancements

• Strengthened root solver with bisection fallback for Newton-Raphson, improving reliability on long-term loans and edge cases.
• Expanded end-to-end tests for extreme scenarios.

Fixed

• Profile builder now correctly honours user-provided start dates in arrears mode.
• Restricted UKConcApp to valid DayCountTimePeriod options.

2.4.0

Added

• Implemented US Appendix J day count convention (Regulation Z) with full unit-period and leap year support.
• Extended DayCountFactor to two-component model (principalFactor + fractionalAdjustment).

Breaking

• Renamed DayCountFactor.factor → principalFactor.

Enhancements

• Improved DayCountFactor string formatting for complex conventions.
• Added comprehensive tests validated against FFIEC APR calculator.

2.3.1

Fixed

• Corrected interest accrual when additional advances occur during repayment phase.

2.3.0

Added

• Unified UK CONC App 1.1 and 1.2 into single UKConcApp class with isSecuredOnLand toggle.

2.2.0

Added

• Implemented UK CONC App 1.1 (secured on land) and UK CONC App 1.2 (unsecured) conventions.

2.1.4

Documentation

• Clarified that EU200848EC remains valid despite directive repeal.

2.1.3

Fixed

• Corrected EU200848EC month-end handling for February 28/29.

2.1.1

Enhancements

• Improved DayCountFactor.toString() and toFoldedString() for long formula rendering.

2.1.0

Changed

• Switched to standard Newton-Raphson solver.

Added

• Actual360 and 30U360 conventions.
• Support for 0–4 decimal precision.

2.0.0

• Updated to Dart SDK ≥3.0.0.
• Dependency refresh and housekeeping.

1.1.1

Added

• Exported UnsolvableException.

Fixed

• README examples.

1.1.0

Added

• Asynchronous computational methods.
• UnsolvableException.

1.0.0

• Initial release.