Chain turbo-stream responses from controllers (and auto append flash messages)

turbo_stream_helpers_concern.rb

#
# What does this do:
#
# Normal: (Basic library usage, without this helper)
# --------------------------------------------------
#  render turbo_stream: [
#    turbo_stream.replace(:flash, partial: 'shared/flash'),
#    turbo_stream.replace(:object, partial: 'partial/name', locals: { object: object } )
#    turbo_stream.replace(:object2, partial: 'partial/name'2, locals: { object2: object2 } )
#  ]
#
# Optimized 1: (flash is included, methods are chainable)
# -------------------------------------------------------
#  render turbo_stream: my_turbo_streamer.replace(:object, partial: 'partial/name', locals: { object: object }
#                                        .replace(:object2, partial: 'partial2/name2', locals: { object2: object2 }
#
#   technical info... ChainableTagBuilder.each is called by the renderer
#
# Optimized 2: (Chained render syntax)
# -----------------------------------
#  my_turbo_streamer
#    .replace(:object, partial: 'partial/name', locals: { object: object }
#    .replace(:object2, partial: 'partial2/name2', locals: { object2: object2 }
#    .render
#
# Optimized 3: (Block Syntax)
# ----------------------------
#  my_turbo_streamer do |s|
#    s.replace(:object, partial: 'partial/name', locals: { object: object }
#    s.replace(:object2, partial: 'partial2/name2', locals: { object2: object2 }
#  end
#

module TurboStreamHelpersConcern
  class ChainableTagBuilder < Turbo::Streams::TagBuilder
    attr_reader :output

    def initialize(controller, view_context, &block)
      super(view_context)
      @output = []
      @controller = controller

      replace(:flash, partial: 'shared/flash') if view_context.flash.present?
      process_block(&block) if block
    end

    # Send an action of the type <tt>name</tt>. Options described in the concrete methods.
    def action(*args, **kwargs, &block)
      @output << super(*args, **kwargs, &block)
      self
    end

    def each(&block)
      output.each(&block)
    end

    def process_block(&block)
      instance_eval(&block)
      render
    end

    def render
      @controller.render turbo_stream: self
    end
  end

  def my_turbo_streamer(**options, &block)
    flash.now[:alert] = options[:alert] if options.key?(:alert)
    flash.now[:notice] = options[:notice] if options.key?(:notice)

    TurboStreamHelpersConcern::ChainableTagBuilder.new(self, view_context, &block)
  end
end