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

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

Overview

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.'

Instance Method Summary collapse

Instance Method Details

#hash_like_case?(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/hash_like_case.rb', line 45

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

#on_case(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/hash_like_case.rb', line 53

def on_case(node)
  return unless min_branches_count?(node)

  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