Class: Hone::Patterns::UniqBy

Inherits:
Base
  • Object
show all
Defined in:
lib/hone/patterns/uniq_by.rb

Overview

Pattern: array.map { }.uniq -> consider array.uniq { }

map { }.uniq creates an intermediate array from map, then deduplicates. If deduplicating on the transformed value, uniq { } avoids the intermediate.

Instance Attribute Summary

Attributes inherited from Base

#findings

Instance Method Summary collapse

Methods inherited from Base

#add_finding, inherited, #initialize, scan_file

Constructor Details

This class inherits a constructor from Hone::Patterns::Base

Instance Method Details

#visit_call_node(node) ⇒ Object 



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# File 'lib/hone/patterns/uniq_by.rb', line 13

def visit_call_node(node)
  super

  # Look for: .uniq where receiver is .map with a block
  return unless node.name == :uniq
  return unless node.arguments.nil? && !block_attached?(node)

  receiver = node.receiver
  return unless receiver.is_a?(Prism::CallNode)
  return unless receiver.name == :map && block_attached?(receiver)

  add_finding(
    node,
    message: "Consider `.uniq { }` instead of `.map { }.uniq` if deduping on transform",
    speedup: "May avoid intermediate array if deduping on transform"
  )
end