Class: Hone::Patterns::CountVsSize

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

Overview

Pattern: array.count (no block) -> array.size or array.length

When count is called without a block on an Array, it's slower than size/length because count is designed for enumerables and does more work. .size and .length are O(1) operations for Arrays as they simply return the cached length, while .count may iterate.

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/count_vs_size.rb', line 15

def visit_call_node(node)
  super
  # Look for: receiver.count with no arguments and no block
  return unless node.name == :count && no_arguments?(node) && node.block.nil?

  add_finding(
    node,
    message: "Use `.size` or `.length` instead of `.count` when counting all elements",
    speedup: "Minor, but `.size` is O(1) for Arrays vs `.count` which may iterate"
  )
end