storing-data.md

Storing data for later use

You can use the on_response, precalculate, save_input_as and calculate methods to store data for later use. These values are stored in the state and are available in the rest of the flow and in the ERB templates.

• precalculate values are available in:
  • The question template
  • The validate block
  • The next_node block
  • The calculate block
  • All subsequent questions and outcomes

NOTE. precalculate blocks are not evaluated in the first question. This is because they're evaluated during the transition of one question to the next.

• on_response values are available in:
  • The validate block
  • The next_node block
  • The calculate block
  • All subsequent questions and outcomes

NOTE. on_response blocks are not named, because they don't automatically store a value in a state variable. In fact doing so is actively discouraged apart from when storing a calculator object in the first question of a flow:

multiple_choice :question_1? do
  option :option_1
  option :option_2

  on_response do |response|
    self.calculator = ExampleCalculator.new
    calculator.question_1_response = response
  end

  next_node do
    if calculator.question_1_response == 'option_1'
      outcome :outcome_1
    else
      outcome :outcome_2
    end
  end
end

value_question :question_2? do
  on_response do |response|
    calculator.question_2_response = response
  end

  next_node do
    if calculator.question_1_response == 'option_1' && calculator.question_2_response == 'London'
      outcome :outcome_1
    else
      outcome :outcome_2
    end
  end
end

• save_input_as values are available in:

  • The calculate block
  • All subsequent questions and outcomes

• calculate values are available in:

  • All subsequent questions and outcomes

The flow below illustrates the data available to the different Question node methods.

multiple_choice :question_1? do
  option :q1_option

  next_node do
    question :question_2?
  end

  calculate :q1_calculated_answer do
    'q1-calculated-answer'
  end
end

multiple_choice :question_2? do
  option :q2_option

  precalculate :q2_precalculated_answer do
    # responses            => ['q1_option']
    # q1_calculated_answer => 'q1-calculated-answer'

    'q2-precalculated-answer'
  end

  on_response do |response|
    # response                => 'q2_option'
    # responses               => ['q1_option']
    # q1_calculated_answer    => 'q1-calculated-answer'
    # q2_precalculated_answer => 'q2_precalculated_answer'

    self.q2_saved_response = response
  end

  validate do |response|
    # response                       => 'q2_option'
    # responses                      => ['q1_option']
    # q1_calculated_answer           => 'q1-calculated-answer'
    # q2_precalculated_answer        => 'q2-precalculated-answer'
    # q2_saved_response              => 'q2_option'
  end

  next_node do |response|
    # response                       => 'q2_option'
    # responses                      => ['q1_option']
    # q1_calculated_answer           => 'q1-calculated-answer'
    # q2_precalculated_answer        => 'q2-precalculated-answer'
    # q2_saved_response              => 'q2_option'
  end

  save_input_as :q2_answer

  calculate :q2_calculated_answer do |response|
    # response                       => 'q2_option'
    # responses                      => ['q1_option', 'q2_option']
    # q1_calculated_answer           => 'q1-calculated-answer'
    # q2_answer                      => 'q2_option'
    # q2_precalculated_answer        => 'q2-precalculated-answer'
    # q2_saved_response              => 'q2_option'
  end
end