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Avoid Callback Chains: Use Domain Events (In-App)

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                  class DomainEvents
  def initialize
    @subscribers = Hash.new { |h, k| h[k] = [] }
  end

  def subscribe(name, &block)
    @subscribers[name] << block
  end

  def publish(name, payload)
    @subscribers[name].each { |sub| sub.call(payload) }
  end
end

                  class Registrations::Create
  def initialize(events: Rails.configuration.domain_events)
    @events = events
  end

  def call(params)
    member = Member.create!(params)
    @events.publish('member.created', member_id: member.id)
    member
  end
end

Callback chains become spooky action at a distance. A simple in-app event bus keeps side effects explicit and testable. This isn’t about Kafka—it’s about clarity and seams.

Sarah Chen

More from Sarah Chen

Avoid Callback Chains: Use Domain Events (In-App)

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More from Sarah Chen