Class: Hone::Patterns::SliceWithLength

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

Overview

Pattern: str[n, str.length] -> str

Endless range syntax avoids the length calculation.

From sqids-ruby commit 9413b68

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/slice_with_length.rb', line 14

def visit_call_node(node)
  super

  # Look for: receiver[offset, receiver.length] pattern
  return unless node.name == :[] && node.arguments

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

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

  # Check if second arg is receiver.length or receiver.size
  return unless second_arg.is_a?(Prism::CallNode)
  return unless %i[length size].include?(second_arg.name)
  return unless nodes_match?(node.receiver, second_arg.receiver)

  add_finding(
    node,
    message: "Use endless range `[#{first_arg.location.slice}..]` instead of `[#{first_arg.location.slice}, #{second_arg.location.slice}]`",
    speedup: "Minor, avoids length calculation"
  )
end