Class: TTY::Prompt::Paginator

Inherits:
Object
  • Object
show all
Defined in:
lib/tty/prompt/paginator.rb

Direct Known Subclasses

BlockPaginator

Constant Summary collapse

DEFAULT_PAGE_SIZE =
6

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(**options) ⇒ Paginator

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Create a Paginator


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# File 'lib/tty/prompt/paginator.rb', line 23

def initialize(**options)
  @last_index  = Array(options[:default]).flatten.first || 0
  @per_page    = options[:per_page]
  @start_index = Array(options[:default]).flatten.first
end

Instance Attribute Details

#current_indexObject (readonly)

The 0-based index of the active item on this page


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# File 'lib/tty/prompt/paginator.rb', line 15

def current_index
  @current_index
end

#end_indexObject (readonly)

The 0-based index of the last item on this page


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# File 'lib/tty/prompt/paginator.rb', line 12

def end_index
  @end_index
end

#last_indexObject (readonly)

The 0-based index of the previously active item on this page


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# File 'lib/tty/prompt/paginator.rb', line 18

def last_index
  @last_index
end

#start_indexObject

The 0-based index of the first item on this page


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# File 'lib/tty/prompt/paginator.rb', line 9

def start_index
  @start_index
end

Instance Method Details

#check_page_size!Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Check if page size is valid

Raises:


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# File 'lib/tty/prompt/paginator.rb', line 42

def check_page_size!
  raise InvalidArgument, "per_page must be > 0" if @per_page < 1
end

#paginate(list, active, per_page = nil, &block) ⇒ Enumerable

Paginate collection given an active index

Parameters:

  • list (Array[Choice])

    a collection of choice items

  • active (Integer)

    current choice active index

  • per_page (Integer) (defaults to: nil)

    number of choice items per page

Returns:

  • (Enumerable)

    the list between start and end index


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# File 'lib/tty/prompt/paginator.rb', line 59

def paginate(list, active, per_page = nil, &block)
  current_index = active - 1
  default_size = (list.size <= DEFAULT_PAGE_SIZE ? list.size : DEFAULT_PAGE_SIZE)
  @per_page = @per_page || per_page || default_size
  check_page_size!
  @start_index ||= (current_index / @per_page) * @per_page
  @end_index ||= @start_index + @per_page - 1

  # Don't paginate short lists
  if list.size <= @per_page
    @start_index = 0
    @end_index = list.size - 1
    if block
      return list.each_with_index(&block)
    else
      return list.each_with_index.to_enum
    end
  end

  step = (current_index - @last_index).abs
  if current_index > @last_index # going up
    if current_index >= @end_index && current_index < list.size - 1
      last_page = list.size - @per_page
      @start_index = [@start_index + step, last_page].min
    end
  elsif current_index < @last_index # going down
    if current_index <= @start_index && current_index > 0
      @start_index = [@start_index - step, 0].max
    end
  end

  # Cycle list
  if current_index.zero?
    @start_index = 0
  elsif current_index == list.size - 1
    @start_index = list.size - 1 - (@per_page - 1)
  end

  @end_index = @start_index + (@per_page - 1)
  @last_index = current_index

  sliced_list = list[@start_index..@end_index]
  page_range = (@start_index..@end_index)

  return sliced_list.zip(page_range).to_enum unless block_given?

  sliced_list.each_with_index do |item, index|
    block[item, @start_index + index]
  end
end

#reset!Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Reset current page indexes


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# File 'lib/tty/prompt/paginator.rb', line 32

def reset!
  @start_index = nil
  @end_index   = nil
end