class RuboCop::Cop::Style::EmptyLiteral

This cop checks for the use of a method, the result of which would be a literal, like an empty array, hash or string.

Constants

ARRAY_NODE

Empty array node

(send

(const nil :Array) :new)
ARR_MSG
HASH_MSG
HASH_NODE

Empty hash node

(send

(const nil :Hash) :new)
STR_MSG
STR_NODE

Empty string node

(send

(const nil :String) :new)

Public Instance Methods

autocorrect(node) click to toggle source
# File lib/rubocop/cop/style/empty_literal.rb, line 45
def autocorrect(node)
  name = case node
         when ARRAY_NODE
           '[]'
         when HASH_NODE
           # `some_method {}` is not same as `some_method Hash.new`
           # because the braces are interpreted as a block, so we avoid
           # the correction. Parentheses around the arguments would
           # solve the problem, but we let the user add those manually.
           return if first_arg_in_method_call_without_parentheses?(node)
           '{}'
         when STR_NODE
           if enforce_double_quotes?
             '""'
           else
             "''"
           end
         end
  ->(corrector) { corrector.replace(node.source_range, name) }
end
on_send(node) click to toggle source
# File lib/rubocop/cop/style/empty_literal.rb, line 31
def on_send(node)
  case node
  when ARRAY_NODE
    add_offense(node, :expression, ARR_MSG)
  when HASH_NODE
    # If Hash.new takes a block, it can't be changed to {}.
    return if node.parent && node.parent.block_type?

    add_offense(node, :expression, HASH_MSG)
  when STR_NODE
    add_offense(node, :expression, STR_MSG)
  end
end

Private Instance Methods

enforce_double_quotes?() click to toggle source
# File lib/rubocop/cop/style/empty_literal.rb, line 68
def enforce_double_quotes?
  string_literals_config['EnforcedStyle'] == 'double_quotes'
end
first_arg_in_method_call_without_parentheses?(node) click to toggle source
# File lib/rubocop/cop/style/empty_literal.rb, line 76
def first_arg_in_method_call_without_parentheses?(node)
  return false unless node.parent && node.parent.send_type?

  _receiver, _method_name, *args = *node.parent
  node.object_id == args.first.object_id && !parentheses?(node.parent)
end
string_literals_config() click to toggle source
# File lib/rubocop/cop/style/empty_literal.rb, line 72
def string_literals_config
  config.for_cop('Style/StringLiterals')
end