Class: RuboCop::Cop::Style::HashLikeCase

Inherits:
Base
  • Object
show all
Defined in:
lib/rubocop/cop/style/hash_like_case.rb

Overview

This cop checks for places where `case-when` represents a simple 1:1 mapping and can be replaced with a hash lookup.

Examples:

MinBranchesCount: 3 (default)

# bad
case country
when 'europe'
  'http://eu.example.com'
when 'america'
  'http://us.example.com'
when 'australia'
  'http://au.example.com'
end

# good
SITES = {
  'europe'    => 'http://eu.example.com',
  'america'   => 'http://us.example.com',
  'australia' => 'http://au.example.com'
}
SITES[country]

MinBranchesCount: 4

# good
case country
when 'europe'
  'http://eu.example.com'
when 'america'
  'http://us.example.com'
when 'australia'
  'http://au.example.com'
end

Constant Summary collapse

MSG =
'Consider replacing `case-when` with a hash lookup.'

Constants inherited from Base

Base::RESTRICT_ON_SEND

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods inherited from Base

#add_global_offense, #add_offense, autocorrect_incompatible_with, badge, #callbacks_needed, callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, #cop_name, cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #ready, #relevant_file?, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

#exclude_limit

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

silence_warnings

Constructor Details

This class inherits a constructor from RuboCop::Cop::Base

Instance Method Details

#hash_like_case?(node) ⇒ Object


43
44
45
46
47
48
49
# File 'lib/rubocop/cop/style/hash_like_case.rb', line 43

def_node_matcher :hash_like_case?, <<~PATTERN
  (case
    _
    (when
      ${str_type? sym_type?}
      $[!nil? recursive_basic_literal?])+ nil?)
PATTERN

#on_case(node) ⇒ Object


51
52
53
54
55
56
57
58
59
# File 'lib/rubocop/cop/style/hash_like_case.rb', line 51

def on_case(node)
  return if node.when_branches.size < min_branches_count

  hash_like_case?(node) do |condition_nodes, body_nodes|
    if nodes_of_same_type?(condition_nodes) && nodes_of_same_type?(body_nodes)
      add_offense(node)
    end
  end
end