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Class: RuboCop::Cop::Style::ConcatArrayLiterals

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::RuboCop::Cop::AutoCorrector, ::RuboCop::Cop::Base, ::RuboCop::ExcludeLimit, NodePattern::Macros, RuboCop::AST::Sexp
Instance Chain:
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/style/concat_array_literals.rb

Overview

Enforces the use of Array#push(item) instead of Array#concat([item]) to avoid redundant array literals.

Examples:

# bad
list.concat([foo])
list.concat([bar, baz])
list.concat([qux, quux], [corge])

# good
list.push(foo)
list.push(bar, baz)
list.push(qux, quux, corge)

Cop Safety Information:

  • This cop is unsafe, as it can produce false positives if the receiver is not an Array object.

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

Class Attribute Summary

::RuboCop::Cop::AutoCorrector - Extended

::RuboCop::Cop::Base - Inherited

.gem_requirements, .lint?,
.support_autocorrect?

Returns if class supports autocorrect.

.support_multiple_source?

Override if your cop should be called repeatedly for multiple investigations Between calls to on_new_investigation and on_investigation_end, the result of processed_source will remain constant.

Class Method Summary

::RuboCop::Cop::Base - Inherited

.autocorrect_incompatible_with

List of cops that should not try to autocorrect at the same time as this cop.

.badge

Naming.

.callbacks_needed, .cop_name, .department,
.documentation_url

Returns an url to view this cops documentation online.

.exclude_from_registry

Call for abstract Cop classes.

.inherited,
.joining_forces

Override and return the Force class(es) you need to join.

.match?

Returns true if the cop name or the cop namespace matches any of the given names.

.new,
.requires_gem

Register a version requirement for the given gem name.

.restrict_on_send

::RuboCop::ExcludeLimit - Extended

exclude_limit

Sets up a configuration option to have an exclude limit tracked.

transform

Instance Attribute Summary

Instance Method Summary

::RuboCop::Cop::Base - Inherited

#add_global_offense

Adds an offense that has no particular location.

#add_offense

Adds an offense on the specified range (or node with an expression) Unless that offense is disabled for this range, a corrector will be yielded to provide the cop the opportunity to autocorrect the offense.

#begin_investigation

Called before any investigation.

#callbacks_needed,
#cop_config

Configuration Helpers.

#cop_name, #excluded_file?,
#external_dependency_checksum

This method should be overridden when a cop’s behavior depends on state that lives outside of these locations:

#inspect
#message

Gets called if no message is specified when calling add_offense or add_global_offense Cops are discouraged to override this; instead pass your message directly.

#name

Alias for Base#cop_name.

#offenses,
#on_investigation_end

Called after all on_…​

#on_new_investigation

Called before all on_…​

#on_other_file

Called instead of all on_…​

#parse

There should be very limited reasons for a Cop to do it’s own parsing.

#parser_engine,
#ready

Called between investigations.

#relevant_file?, #target_rails_version, #target_ruby_version, #annotate, #apply_correction, #attempt_correction,
#callback_argument

Reserved for Cop::Cop.

#complete_investigation

Called to complete an investigation.

#correct, #current_corrector,
#current_offense_locations

Reserved for Commissioner:

#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?, #file_name_matches_any?, #find_message, #find_severity, #range_for_original, #range_from_node_or_range,
#reset_investigation

Actually private methods.

#use_corrector

::RuboCop::Cop::AutocorrectLogic - Included

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

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

Instance Method Details

#offense_range(node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/concat_array_literals.rb', line 70

def offense_range(node)
  node.loc.selector.join(node.source_range.end)
end

#on_csend(node)

Alias for #on_send.

[ GitHub ]

  
# File 'lib/rubocop/cop/style/concat_array_literals.rb', line 66

alias on_csend on_send

#on_send(node) Also known as: #on_csend

[ GitHub ]

  
# File 'lib/rubocop/cop/style/concat_array_literals.rb', line 34

def on_send(node)
  return if node.arguments.empty?
  return unless node.arguments.all?(&:array_type?)

  offense = offense_range(node)
  current = offense.source

  if (use_percent_literal = node.arguments.any?(&:percent_literal?))
    if percent_literals_includes_only_basic_literals?(node)
      prefer = preferred_method(node)
      message = format(MSG, prefer: prefer, current: current)
    else
      message = format(MSG_FOR_PERCENT_LITERALS, current: current)
    end
  else
    prefer = preferred_method(node)
    message = format(MSG, prefer: prefer, current: current)
  end

  add_offense(offense, message: message) do |corrector|
    if use_percent_literal
      corrector.replace(offense, prefer)
    else
      corrector.replace(node.loc.selector, 'push')
      node.arguments.each do |argument|
        corrector.remove(argument.loc.begin)
        corrector.remove(argument.loc.end)
      end
    end
  end
end

#percent_literals_includes_only_basic_literals?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/concat_array_literals.rb', line 87

def percent_literals_includes_only_basic_literals?(node)
  node.arguments.select(&:percent_literal?).all? do |arg|
    arg.children.all? { |child| child.str_type? || child.sym_type? }
  end
end

#preferred_method(node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/concat_array_literals.rb', line 74

def preferred_method(node)
  new_arguments =
    node.arguments.map do |arg|
      if arg.percent_literal?
        arg.children.map { |child| child.value.inspect }
      else
        arg.children.map(&:source)
      end
    end.join(', ')

  "push(#{new_arguments})"
end