Class: Hone::Patterns::RedundantStringChars

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

Overview

Detects str.chars[i] which should be str[i]

str.chars creates an array of single-character strings, then indexes it. Direct string indexing is much faster.

Examples:

Bad

str.chars[0]
str.chars.first
str.chars.last

Good

str[0]
str[0]
str[-1]

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/redundant_string_chars.rb', line 24

def visit_call_node(node)
  if chained_chars_index?(node)
    replacement = suggest_replacement(node)
    add_finding(
      node,
      message: "Use `#{replacement}` instead of `chars[...]` to avoid array allocation",
      speedup: "Significant - avoids creating array of all characters"
    )
  elsif chained_chars_first_last?(node)
    replacement = suggest_first_last_replacement(node)
    add_finding(
      node,
      message: "Use `#{replacement}` instead of `chars.#{node.name}` to avoid array allocation",
      speedup: "Significant - avoids creating array of all characters"
    )
  end

  super
end