Class: Reacto::Operations::Extremums

Inherits:
Object
  • Object
show all
Defined in:
lib/reacto/operations/extremums.rb

Constant Summary collapse

AVAILABLE_TYPES = 
%i(min max minmax)

Instance Method Summary collapse

Constructor Details

#initialize(action: nil, by: nil, type: :max) ⇒ Extremums

Returns a new instance of Extremums.



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# File 'lib/reacto/operations/extremums.rb', line 8

def initialize(action: nil, by: nil, type: :max)
  unless AVAILABLE_TYPES.include?(type)
    raise ArgumentError.new(
      "Type not supported, expecting one of #{AVAILABLE_TYPES.join(', ')}"
    )
  end

  @action = action
  @by = by
  @type = type
end

Instance Method Details

#call(tracker) ⇒ Object 



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# File 'lib/reacto/operations/extremums.rb', line 20

def call(tracker)
  buffer = []

  behaviour = -> (v) do
    buffer << v
  end

  error = -> (e) do
    emit_values(tracker, buffer)
    tracker.on_error(e)
  end

  close = -> () do
    emit_values(tracker, buffer)
    tracker.on_close
  end

  Subscriptions::OperationSubscription.new(
    tracker, error: error, value: behaviour, close: close
  )
end

#emit_values(tracker, buffer) ⇒ Object 



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# File 'lib/reacto/operations/extremums.rb', line 42

def emit_values(tracker, buffer)
  values =
    if @by
      buffer.send("#{@type.to_s}_by", &@by)
    else
      buffer.send(@type, &@action)
    end

  Array(values).each { |val| tracker.on_value(val) }
end