Class: Hone::Patterns::StringDeletePrefix

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

Overview

Pattern: str.sub(/^prefix/, '') -> str.delete_prefix('prefix')

delete_prefix is a specialized method that avoids the regex engine overhead. It's approximately 2x faster for this common use case.

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/string_delete_prefix.rb', line 13

def visit_call_node(node)
  super

  return unless node.name == :sub

  args = node.arguments&.arguments
  return unless args&.size == 2

  first_arg = args[0]
  second_arg = args[1]

  # Check if first arg is a regex starting with ^
  return unless first_arg.is_a?(Prism::RegularExpressionNode)
  return unless second_arg.is_a?(Prism::StringNode) && second_arg.content.empty?

  pattern = first_arg.content
  return unless pattern.start_with?("^")

  # Extract the literal prefix (after ^)
  prefix = pattern[1..]

  # Only suggest for simple literal prefixes (no regex metacharacters)
  return unless simple_literal?(prefix)

  add_finding(
    node,
    message: "Use `.delete_prefix('#{prefix}')` instead of `.sub(/^#{prefix}/, '')`",
    speedup: "Avoids regex engine overhead"
  )
end