Class: ReactiveCount

Inherits:
Object show all
Includes:
ReactiveTags
Defined in:
lib/volt/reactive/reactive_count.rb

Instance Method Summary collapse

Methods included from ReactiveTags

included, #reactive_method_tag

Constructor Details

#initialize(source, block) ⇒ ReactiveCount

Returns a new instance of ReactiveCount.



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# File 'lib/volt/reactive/reactive_count.rb', line 8

def initialize(source, block)
  @source = ReactiveValue.new(source)
  @block = block
end

Instance Method Details

#cached_count ⇒ Object

After events are bound, we keep a cache of each cell’s count value, and base the results



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# File 'lib/volt/reactive/reactive_count.rb', line 19

def cached_count

end

#change_cell_count(size) ⇒ Object

We need to make sure we’re listening on the result from each cell, that way we can trigger when the value changes.



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# File 'lib/volt/reactive/reactive_count.rb', line 57

def change_cell_count(size)
  current_size = @cell_trackers.size

  if current_size < size
    # Add trackers

    current_size.upto(size-1) do |index|
      # Get the reactive value for the index
      val = @source[index]

      result = @block.call(val)
      # puts "TRACK AT #{index} on #{result.inspect}"

      @cell_trackers << result.on('changed') do
        trigger!('changed')
      end
    end
  elsif current_size > size
    (current_size-1).downto(size) do |index|
      # puts "Remove at: #{index}"
      @cell_trackers[index].remove
      @cell_trackers.delete_at(index)
    end
  end
end

#cur ⇒ Object 



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# File 'lib/volt/reactive/reactive_count.rb', line 13

def cur
  direct_count
end

#direct_count ⇒ Object

Before events are bound, when .cur is called, we simply run the count on the source object.



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# File 'lib/volt/reactive/reactive_count.rb', line 25

def direct_count
  count = 0
  @source.size.cur.times do |index|
    val = @source[index]
    result = @block.call(val).cur
    if result == true
      count += 1
    end
  end

  count
end

#event_added(event, scope_provider, first, first_for_event) ⇒ Object 



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# File 'lib/volt/reactive/reactive_count.rb', line 97

def event_added(event, scope_provider, first, first_for_event)
  setup_listeners if first
end

#event_removed(event, last, last_for_event) ⇒ Object 



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# File 'lib/volt/reactive/reactive_count.rb', line 101

def event_removed(event, last, last_for_event)
  teardown_listeners if last
end

#inspect ⇒ Object 



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# File 'lib/volt/reactive/reactive_count.rb', line 105

def inspect
  "@#{cur}"
end

#reactive? ⇒ Boolean

Returns:



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# File 'lib/volt/reactive/reactive_count.rb', line 4

def reactive?
  true
end

#setup_listeners ⇒ Object 



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# File 'lib/volt/reactive/reactive_count.rb', line 38

def setup_listeners
  puts "SETUP LISTENERS"
  @cell_trackers = []
  @added_tracker = @source.on('added') do |_, index|
    change_cell_count(@source.size.cur)
    trigger!('changed')
  end

  @removed_tracker = @source.on('removed') do |_, index|
    change_cell_count(@source.size.cur)
    trigger!('changed')
  end

  # Initial cell tracking
  change_cell_count(@source.size.cur)
end

#teardown_listeners ⇒ Object 



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# File 'lib/volt/reactive/reactive_count.rb', line 84

def teardown_listeners
  @added_tracker.remove
  @added_tracker = nil

  @removed_tracker.remove
  @removed_tracker = nil

  change_cell_count(0)

  @cell_trackers = nil
  puts "TEARDOWN"
end