This package provides a library for representing local dates that are independent of the time zone.

A date of birth represented as a special case of local date with ability to determine the age.

Features

• Representation of local date (see LocalDate API):
  • Creation from DateTime;
  • Conversion to DateTime;
  • Generic API for implementation of different formatting;
  • Generic API for implementation of different format parsing;
  • Support of formatting/parsing of ISO8601 representation of date;
  • Comparison of local dates.
• Representation of a date of birth as a special case of local date (see DateOfBirth API):
  • Calculation of the age on the given date with handling of leap date of birth;
  • Determination of a birthday date in the specified year with handling of leap date of birth.

Getting started

1. Install the package as a dependency:

   dart pub add local_date

2. Make the import:

   import 'package:local_date/local_date.dart';

Usage

Parsing / formatting

Parse ISO 8601 string representation:

final date = LocalDate.parse('2023-11-15', parser: ISO8610Format());

Format as ISO 8601 string:

final date = LocalDate.of(2023, 11, 15);

assert(date.formattedBy(ISO8601Format()) == '2023-11-15');

Feel free to implement DateFormatter and DateParser generic interfaces for custom representations.

Working with dates of birth

Interpretation of the date of birth is not so straightforward as most of us used to think about.

One of the most widespread mistake is a wrong interpretation of leap dates of birth. If a person has date of birth on February 29th, the birthday in a non-leap year must be February 28th, not March 1st.

Fortunately, this library encapsulates correct logic inside DateOfBirth.

Let's see the example:

final leapDateOfBirth = DateOfBirth.of(2000, 2, 29);

// Age will be incremented on since February 28 in a non-leap lear:
assert(leapDateOfBirth.calculateAgeAsOnDate(LocalDate.of(2003, 2, 28)) == 3);

// Age will be incremented on since February 29 in a leap lear:
assert(leapDateOfBirth.calculateAgeAsOnDate(LocalDate.of(2004, 2, 28)) == 3);
assert(leapDateOfBirth.calculateAgeAsOnDate(LocalDate.of(2004, 2, 29)) == 3);
assert(leapDateOfBirth.calculateAgeAsOnDate(LocalDate.of(2004, 12, 31)) == 3);

Additional information

Limitations

This implementation works with the Gregorian calendar only and limits set of years to the range from 0 to 9999. This range covers the most of the enterprise related issues.