String assignment to date attribute taking account of timezone

README.md

Sometimes we want to handle date as Date in JavaScript and JavaScript's JSON.parse converts Date to an string in UTC ISO 8601 format.

JSON.stringify({ date: new Date(2015, 2, 14) })
// "{"date":"2015-03-13T15:00:00.000Z"}"

ActiveRecord's date attribute doesn't take timezone into account when it converts string to date.

class Application < Rails::Application
  config.time_zone = 'Tokyo'
end

class Person < ActiveRecord::Base
  # birth_date :date
end

expect(Person.new(birth_date: '2015-02-13T15:00:00.000Z').birth_date)
  .to eq(Date.new(2015, 2, 13))

StringDateAssignmentWithTimezone concern overrides date attribute mutators in your ActiveRecord model to take timezone into account.

class Person < ActiveRecord::Base
  include StringDateAssignmentWithTimezone
end

expect(Person.new(birth_date: '2015-02-13T15:00:00.000Z').birth_date)
  .to eq(Date.new(2015, 2, 14))

string_date_assignment_with_timezone.rb

module StringDateAssignmentWithTimezone
  extend ActiveSupport::Concern
 
  included do
    columns_hash.each do |name, col|
      next unless col.type == :date
      define_method("#{name}=") do |value|
        time = value.is_a?(String) ? Time.zone.parse(value) : value
        self[name] = time
      end
    end
  end
end