Module: Trailblazer::Activity::Adds::Insert

Defined in:
lib/trailblazer/activity/adds.rb

Overview

Functions to alter the Sequence/Pipeline by inserting, replacing, or deleting a row.

they don’t mutate the data structure but rebuild it, has to respond to to_a

These methods are invoked via apply_adds and should never be called directly.

Class Method Summary collapse

Class Method Details

.Append(pipeline, new_row, insert_id = nil) ⇒ Object

Append new_row after insert_id.



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# File 'lib/trailblazer/activity/adds.rb', line 70

def Append(pipeline, new_row, insert_id = nil)
  build_from_ary(pipeline, insert_id) do |ary, index|
    index = ary.size if index.nil? # append to end of pipeline.

    range_before_index(ary, index + 1) + [new_row] + Array(ary[index + 1..-1])
  end
end

.apply_on_ary(pipeline, insert_id, raise_index_error: true, &block) ⇒ Object

Converts the pipeline structure to an array, automatically finds the index for insert_id, and calls the user block with the computed values.

Single-entry point, could be named #call.



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# File 'lib/trailblazer/activity/adds.rb', line 115

def apply_on_ary(pipeline, insert_id, raise_index_error: true, &block)
  ary = pipeline.to_a

  if insert_id.nil?
    index = nil
  else
    index = find_index(ary, insert_id) # DISCUSS: this only makes sense if there are more than {Append} using this.
    raise IndexError.new(pipeline, insert_id) if index.nil? && raise_index_error
  end

  _new_ary = yield(ary, index) # call the block.
end

.build(sequence, rows) ⇒ Object 



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# File 'lib/trailblazer/activity/adds.rb', line 100

def build(sequence, rows)
  sequence.class.new(rows)
end

.build_from_ary(pipeline, insert_id, &block) ⇒ Object 



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# File 'lib/trailblazer/activity/adds.rb', line 128

def build_from_ary(pipeline, insert_id, &block)
  new_ary = apply_on_ary(pipeline, insert_id, &block)

  # Wrap the sequence/pipeline array into a concrete Sequence/Pipeline.
  build(pipeline, new_ary)
end

.Delete(pipeline, _, insert_id) ⇒ Object 



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# File 'lib/trailblazer/activity/adds.rb', line 93

def Delete(pipeline, _, insert_id)
  build_from_ary(pipeline, insert_id) do |ary, index|
    range_before_index(ary, index) + ary[index + 1..-1]
  end
end

.find_index(ary, insert_id) ⇒ Object 



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# File 'lib/trailblazer/activity/adds.rb', line 105

def find_index(ary, insert_id)
  ary.find_index { |row| row.id == insert_id }
end

.Prepend(pipeline, new_row, insert_id = nil) ⇒ Object

Insert new_row before insert_id.



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# File 'lib/trailblazer/activity/adds.rb', line 79

def Prepend(pipeline, new_row, insert_id = nil)
  build_from_ary(pipeline, insert_id) do |ary, index|
    index = 0 if index.nil? # Prepend to beginning of pipeline.

    range_before_index(ary, index) + [new_row] + ary[index..-1]
  end
end

.range_before_index(ary, index) ⇒ Object

Always returns a valid, concat-able array for all indices before the index.



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# File 'lib/trailblazer/activity/adds.rb', line 138

def range_before_index(ary, index)
  return [] if index == 0
  ary[0..index - 1]
end

.Replace(pipeline, new_row, insert_id) ⇒ Object 



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# File 'lib/trailblazer/activity/adds.rb', line 87

def Replace(pipeline, new_row, insert_id)
  build_from_ary(pipeline, insert_id) do |ary, index|
    range_before_index(ary, index) + [new_row] + ary[index + 1..-1]
  end
end